Added fuzz tests for mini table building and binary format parsing/serialization.

PiperOrigin-RevId: 458240180
diff --git a/BUILD b/BUILD
index 1dd45e6..f49f4c2 100644
--- a/BUILD
+++ b/BUILD
@@ -511,6 +511,7 @@
     name = "msg_test",
     srcs = ["upb/msg_test.cc"],
     deps = [
+        ":fuzz_test_util",
         ":json",
         ":msg_test_upb_proto",
         ":msg_test_upb_proto_reflection",
@@ -704,6 +705,17 @@
     deps = ["@bazel_tools//tools/bash/runfiles"],
 )
 
+cc_library(
+    name = "fuzz_test_util",
+    testonly = 1,
+    srcs = ["upb/fuzz_test_util.cc"],
+    hdrs = ["upb/fuzz_test_util.h"],
+    deps = [
+        ":mini_table",
+        ":upb",
+    ],
+)
+
 # Internal C/C++ libraries #####################################################
 
 cc_library(