Remove empty tests properties. (#41461)

Tests property is optional, empty tests property can be safely removed from the build configurations.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
diff --git a/ci/builders/linux_android_aot_engine.json b/ci/builders/linux_android_aot_engine.json
index 7453048..5e03a1d 100644
--- a/ci/builders/linux_android_aot_engine.json
+++ b/ci/builders/linux_android_aot_engine.json
@@ -34,8 +34,7 @@
                     "flutter/shell/platform/android:embedding_jars",
                     "flutter/shell/platform/android:abi_jars"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -71,8 +70,7 @@
                     "flutter/shell/platform/android:embedding_jars",
                     "flutter/shell/platform/android:abi_jars"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -109,8 +107,7 @@
                     "flutter/shell/platform/android:abi_jars",
                     "flutter/shell/platform/android:analyze_snapshot"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -146,8 +143,7 @@
                     "flutter/shell/platform/android:abi_jars",
                     "flutter/shell/platform/android:analyze_snapshot"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -184,8 +180,7 @@
                     "flutter/shell/platform/android:abi_jars",
                     "flutter/shell/platform/android:analyze_snapshot"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -222,9 +217,7 @@
                     "flutter/shell/platform/android:abi_jars",
                     "flutter/shell/platform/android:analyze_snapshot"
                 ]
-            },
-            "tests": []
+            }
         }
-    ],
-    "tests": []
+    ]
 }
diff --git a/ci/builders/linux_android_debug_engine.json b/ci/builders/linux_android_debug_engine.json
index 750974b..7dec143 100644
--- a/ci/builders/linux_android_debug_engine.json
+++ b/ci/builders/linux_android_debug_engine.json
@@ -131,8 +131,7 @@
                     "flutter",
                     "flutter/shell/platform/android:abi_jars"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -163,8 +162,7 @@
                     "flutter",
                     "flutter/shell/platform/android:abi_jars"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -195,9 +193,7 @@
                     "flutter",
                     "flutter/shell/platform/android:abi_jars"
                 ]
-            },
-            "tests": []
+            }
         }
-    ],
-    "tests": []
+    ]
 }
diff --git a/ci/builders/linux_arm_host_engine.json b/ci/builders/linux_arm_host_engine.json
index 88edda5..d4645e1 100644
--- a/ci/builders/linux_arm_host_engine.json
+++ b/ci/builders/linux_arm_host_engine.json
@@ -32,8 +32,7 @@
                 "targets": [
                     "flutter/shell/platform/linux:flutter_gtk"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -72,8 +71,7 @@
                     "flutter/tools/font-subset",
                     "flutter/shell/platform/linux:flutter_gtk"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -106,9 +104,7 @@
                 "targets": [
                     "flutter/shell/platform/linux:flutter_gtk"
                 ]
-            },
-            "tests": []
+            }
         }
-    ],
-    "tests": []
+    ]
 }
diff --git a/ci/builders/linux_host_desktop_engine.json b/ci/builders/linux_host_desktop_engine.json
index f9368b0..6d9773a 100644
--- a/ci/builders/linux_host_desktop_engine.json
+++ b/ci/builders/linux_host_desktop_engine.json
@@ -30,8 +30,7 @@
                 "targets": [
                     "flutter/shell/platform/linux:flutter_gtk"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -64,8 +63,7 @@
                 "targets": [
                     "flutter/shell/platform/linux:flutter_gtk"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -97,9 +95,7 @@
                 "targets": [
                     "flutter/shell/platform/linux:flutter_gtk"
                 ]
-            },
-            "tests": []
+            }
         }
-    ],
-    "tests": []
+    ]
 }
diff --git a/ci/builders/linux_host_engine.json b/ci/builders/linux_host_engine.json
index 5c90e31..240bb81 100644
--- a/ci/builders/linux_host_engine.json
+++ b/ci/builders/linux_host_engine.json
@@ -22,8 +22,7 @@
                     "flutter",
                     "flutter/sky/packages"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [],
@@ -230,6 +229,5 @@
                 }
             ]
         }
-    ],
-    "tests": []
+    ]
 }
diff --git a/ci/builders/mac_android_aot_engine.json b/ci/builders/mac_android_aot_engine.json
index 6ab0ef5..ecd6cc8 100644
--- a/ci/builders/mac_android_aot_engine.json
+++ b/ci/builders/mac_android_aot_engine.json
@@ -32,8 +32,7 @@
                     "flutter/lib/snapshot",
                     "flutter/shell/platform/android:gen_snapshot"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -68,8 +67,7 @@
                     "flutter/lib/snapshot",
                     "flutter/shell/platform/android:gen_snapshot"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -104,8 +102,7 @@
                     "flutter/lib/snapshot",
                     "flutter/shell/platform/android:gen_snapshot"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -139,8 +136,7 @@
                     "flutter/lib/snapshot",
                     "flutter/shell/platform/android:gen_snapshot"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -175,8 +171,7 @@
                     "flutter/lib/snapshot",
                     "flutter/shell/platform/android:gen_snapshot"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -211,11 +206,9 @@
                     "flutter/lib/snapshot",
                     "flutter/shell/platform/android:gen_snapshot"
                 ]
-            },
-            "tests": []
+            }
         }
     ],
-    "tests": [],
     "generators": [],
     "archives": []
 }
diff --git a/ci/builders/mac_host_engine.json b/ci/builders/mac_host_engine.json
index 9be8803..4291cb2 100644
--- a/ci/builders/mac_host_engine.json
+++ b/ci/builders/mac_host_engine.json
@@ -214,8 +214,7 @@
                     "flutter/build/archives:dart_sdk_archive",
                     "flutter/shell/platform/darwin/macos:zip_macos_flutter_framework"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -252,8 +251,7 @@
                     "flutter/build/archives:artifacts",
                     "flutter/shell/platform/darwin/macos:zip_macos_flutter_framework"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -292,11 +290,9 @@
                     "flutter/build/archives:artifacts",
                     "flutter/shell/platform/darwin/macos:zip_macos_flutter_framework"
                 ]
-            },
-            "tests": []
+            }
         }
     ],
-    "tests": [],
     "generators": {
         "tasks": [
             {
diff --git a/ci/builders/mac_impeller_cmake_example.json b/ci/builders/mac_impeller_cmake_example.json
index 8986c1a..5a9596d 100644
--- a/ci/builders/mac_impeller_cmake_example.json
+++ b/ci/builders/mac_impeller_cmake_example.json
@@ -20,9 +20,7 @@
                 "config": "impeller-cmake-example",
                 "targets": [
                 ]
-            },
-            "tests": []
+            }
         }
-    ],
-    "tests": []
+    ]
 }
diff --git a/ci/builders/mac_unopt.json b/ci/builders/mac_unopt.json
index 00da05d..c9b4e50 100644
--- a/ci/builders/mac_unopt.json
+++ b/ci/builders/mac_unopt.json
@@ -156,8 +156,7 @@
                 "$flutter/osx_sdk": {
                     "sdk_version": "14c18"
                 }
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -231,6 +230,5 @@
 
             ]
         }
-    ],
-    "tests": []
+    ]
 }
diff --git a/ci/builders/windows_arm_host_engine.json b/ci/builders/windows_arm_host_engine.json
index 83da000..8fad758 100644
--- a/ci/builders/windows_arm_host_engine.json
+++ b/ci/builders/windows_arm_host_engine.json
@@ -42,8 +42,7 @@
                     "flutter/shell/platform/windows/client_wrapper:client_wrapper_archive",
                     "flutter/build/archives:windows_flutter"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -79,8 +78,7 @@
                     "gen_snapshot",
                     "flutter/build/archives:windows_flutter"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -117,8 +115,7 @@
                     "gen_snapshot",
                     "flutter/build/archives:windows_flutter"
                 ]
-            },
-            "tests": []
+            }
         }
     ]
 }
diff --git a/ci/builders/windows_host_engine.json b/ci/builders/windows_host_engine.json
index e507a79..289fa7b 100644
--- a/ci/builders/windows_host_engine.json
+++ b/ci/builders/windows_host_engine.json
@@ -87,8 +87,7 @@
                     "gen_snapshot",
                     "flutter/build/archives:windows_flutter"
                 ]
-            },
-            "tests": []
+            }
         },
         {
             "archives": [
@@ -122,8 +121,7 @@
                     "gen_snapshot",
                     "flutter/build/archives:windows_flutter"
                 ]
-            },
-            "tests": []
+            }
         }
     ]
 }