More consistent temp directory naming (#42063)

Applying our style guide:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#have-good-hygiene-when-using-temporary-directories
diff --git a/packages/flutter_tools/test/general.shard/android/gradle_test.dart b/packages/flutter_tools/test/general.shard/android/gradle_test.dart
index f8afc24..5c6434d 100644
--- a/packages/flutter_tools/test/general.shard/android/gradle_test.dart
+++ b/packages/flutter_tools/test/general.shard/android/gradle_test.dart
@@ -444,7 +444,7 @@
 
     setUp(() {
       mockLogger = BufferLogger();
-      tempDir = fs.systemTempDirectory.createTempSync('settings_aar_test.');
+      tempDir = fs.systemTempDirectory.createTempSync('flutter_settings_aar_test.');
 
     });
 
@@ -852,7 +852,7 @@
 
     setUp(() {
       fs = MemoryFileSystem();
-      tempDir = fs.systemTempDirectory.createTempSync('artifacts_test.');
+      tempDir = fs.systemTempDirectory.createTempSync('flutter_artifacts_test.');
       gradleBinary = platform.isWindows ? 'gradlew.bat' : 'gradlew';
       gradleWrapperDirectory = fs.directory(
         fs.path.join(tempDir.path, 'bin', 'cache', 'artifacts', 'gradle_wrapper'));
@@ -960,7 +960,7 @@
 
     setUp(() {
       memoryFileSystem = MemoryFileSystem();
-      tempDir = memoryFileSystem.systemTempDirectory.createTempSync('artifacts_test.');
+      tempDir = memoryFileSystem.systemTempDirectory.createTempSync('flutter_artifacts_test.');
       gradleWrapperDirectory = memoryFileSystem.directory(
           memoryFileSystem.path.join(tempDir.path, 'bin', 'cache', 'artifacts', 'gradle_wrapper'));
       gradleWrapperDirectory.createSync(recursive: true);
@@ -1157,7 +1157,7 @@
     });
 
     testUsingContext('returns true when the project is using AndroidX', () async {
-      final Directory androidDirectory = fs.systemTempDirectory.createTempSync('android.');
+      final Directory androidDirectory = fs.systemTempDirectory.createTempSync('flutter_android.');
 
       androidDirectory
         .childFile('gradle.properties')
@@ -1170,7 +1170,7 @@
     });
 
     testUsingContext('returns false when the project is not using AndroidX', () async {
-      final Directory androidDirectory = fs.systemTempDirectory.createTempSync('android.');
+      final Directory androidDirectory = fs.systemTempDirectory.createTempSync('flutter_android.');
 
       androidDirectory
         .childFile('gradle.properties')
@@ -1183,7 +1183,7 @@
     });
 
     testUsingContext('returns false when gradle.properties does not exist', () async {
-      final Directory androidDirectory = fs.systemTempDirectory.createTempSync('android.');
+      final Directory androidDirectory = fs.systemTempDirectory.createTempSync('flutter_android.');
 
       expect(isAppUsingAndroidX(androidDirectory), isFalse);
 
@@ -1313,7 +1313,7 @@
       mockProcessManager = MockProcessManager();
       android = fakePlatform('android');
 
-      final Directory tempDir = fs.systemTempDirectory.createTempSync('artifacts_test.');
+      final Directory tempDir = fs.systemTempDirectory.createTempSync('flutter_artifacts_test.');
       cache = Cache(rootOverride: tempDir);
 
       final Directory gradleWrapperDirectory = tempDir
diff --git a/packages/flutter_tools/test/general.shard/application_package_test.dart b/packages/flutter_tools/test/general.shard/application_package_test.dart
index 52b4964..9ea78aa 100644
--- a/packages/flutter_tools/test/general.shard/application_package_test.dart
+++ b/packages/flutter_tools/test/general.shard/application_package_test.dart
@@ -107,7 +107,7 @@
         .childFile('gradle.properties')
         .writeAsStringSync('irrelevant');
 
-      final Directory gradleWrapperDir = fs.systemTempDirectory.createTempSync('gradle_wrapper.');
+      final Directory gradleWrapperDir = fs.systemTempDirectory.createTempSync('flutter_application_package_test_gradle_wrapper.');
       when(mockCache.getArtifactDirectory('gradle_wrapper')).thenReturn(gradleWrapperDir);
 
       fs.directory(gradleWrapperDir.childDirectory('gradle').childDirectory('wrapper'))
diff --git a/packages/flutter_tools/test/general.shard/artifacts_test.dart b/packages/flutter_tools/test/general.shard/artifacts_test.dart
index 7947428..2086547 100644
--- a/packages/flutter_tools/test/general.shard/artifacts_test.dart
+++ b/packages/flutter_tools/test/general.shard/artifacts_test.dart
@@ -19,7 +19,7 @@
 
     setUp(() {
       memoryFileSystem = MemoryFileSystem();
-      tempDir = memoryFileSystem.systemTempDirectory.createTempSync('artifacts_test.');
+      tempDir = memoryFileSystem.systemTempDirectory.createTempSync('flutter_artifacts_test.');
     });
 
     tearDown(() {
diff --git a/packages/flutter_tools/test/general.shard/cache_test.dart b/packages/flutter_tools/test/general.shard/cache_test.dart
index 5a15cb7..cc6bb62 100644
--- a/packages/flutter_tools/test/general.shard/cache_test.dart
+++ b/packages/flutter_tools/test/general.shard/cache_test.dart
@@ -234,8 +234,8 @@
     });
 
     testUsingContext('makes binary dirs readable and executable by all', () async {
-      final Directory artifactDir = fs.systemTempDirectory.createTempSync('artifact.');
-      final Directory downloadDir = fs.systemTempDirectory.createTempSync('download.');
+      final Directory artifactDir = fs.systemTempDirectory.createTempSync('flutter_cache_test_artifact.');
+      final Directory downloadDir = fs.systemTempDirectory.createTempSync('flutter_cache_test_download.');
       when(mockCache.getArtifactDirectory(any)).thenReturn(artifactDir);
       when(mockCache.getDownloadDir()).thenReturn(downloadDir);
       final FakeCachedArtifact artifact = FakeCachedArtifact(
@@ -282,7 +282,7 @@
       final AndroidMavenArtifacts mavenArtifacts = AndroidMavenArtifacts();
       expect(mavenArtifacts.isUpToDate(), isFalse);
 
-      final Directory gradleWrapperDir = fs.systemTempDirectory.createTempSync('gradle_wrapper.');
+      final Directory gradleWrapperDir = fs.systemTempDirectory.createTempSync('flutter_cache_test_gradle_wrapper.');
       when(mockCache.getArtifactDirectory('gradle_wrapper')).thenReturn(gradleWrapperDir);
 
       fs.directory(gradleWrapperDir.childDirectory('gradle').childDirectory('wrapper'))
diff --git a/packages/flutter_tools/test/general.shard/plugins_test.dart b/packages/flutter_tools/test/general.shard/plugins_test.dart
index 1528828..073fee4 100644
--- a/packages/flutter_tools/test/general.shard/plugins_test.dart
+++ b/packages/flutter_tools/test/general.shard/plugins_test.dart
@@ -197,7 +197,7 @@
       when(androidProject.appManifestFile).thenReturn(androidManifest);
 
       final Directory pluginUsingJavaAndNewEmbeddingDir =
-        fs.systemTempDirectory.createTempSync('pluginUsingJavaAndNewEmbeddingDir.');
+        fs.systemTempDirectory.createTempSync('flutter_plugin_using_java_and_new_embedding_dir.');
       pluginUsingJavaAndNewEmbeddingDir
         .childFile('pubspec.yaml')
         .writeAsStringSync('''
@@ -217,7 +217,7 @@
         ..writeAsStringSync('import io.flutter.embedding.engine.plugins.FlutterPlugin;');
 
       final Directory pluginUsingKotlinAndNewEmbeddingDir =
-        fs.systemTempDirectory.createTempSync('pluginUsingKotlinAndNewEmbeddingDir.');
+        fs.systemTempDirectory.createTempSync('flutter_plugin_using_kotlin_and_new_embedding_dir.');
       pluginUsingKotlinAndNewEmbeddingDir
         .childFile('pubspec.yaml')
         .writeAsStringSync('''
@@ -237,7 +237,7 @@
         ..writeAsStringSync('import io.flutter.embedding.engine.plugins.FlutterPlugin');
 
       final Directory pluginUsingOldEmbeddingDir =
-        fs.systemTempDirectory.createTempSync('pluginUsingOldEmbeddingDir.');
+        fs.systemTempDirectory.createTempSync('flutter_plugin_using_old_embedding_dir.');
       pluginUsingOldEmbeddingDir
         .childFile('pubspec.yaml')
         .writeAsStringSync('''
diff --git a/packages/flutter_tools/test/general.shard/resident_runner_test.dart b/packages/flutter_tools/test/general.shard/resident_runner_test.dart
index b86a76a..6de86c6 100644
--- a/packages/flutter_tools/test/general.shard/resident_runner_test.dart
+++ b/packages/flutter_tools/test/general.shard/resident_runner_test.dart
@@ -306,7 +306,7 @@
   }));
 
   test('ResidentRunner uses temp directory when there is no output dill path', () => testbed.run(() {
-    expect(residentRunner.artifactDirectory.path, contains('_fluttter_tool'));
+    expect(residentRunner.artifactDirectory.path, contains('flutter_tool.'));
 
     final ResidentRunner otherRunner = HotRunner(
       <FlutterDevice>[