Fix typo "SetTestFluttterStub", "FluttterActivity" and "implementantions" (#33551)

As recommended in #33547 (comment), I fixed all typos in one PR.

Fixes flutter/flutter#104366
Fixes flutter/flutter#104367
Fixes flutter/flutter#104368
Fixes flutter/flutter#104369
Fixes flutter/flutter#104370

Author: nilsreichardt

shell/platform/android/io/flutter/embedding/android/FlutterActivity.java

@@ -1133,7 +1133,7 @@ public void cleanUpFlutterEngine(@NonNull FlutterEngine flutterEngine) {
    * {@link io.flutter.embedding.engine.FlutterEngine} to outlive this {@code FlutterActivity} so
    * that it can be used later in a different {@code Activity}. To accomplish this, the {@link
    * io.flutter.embedding.engine.FlutterEngine} may need to be disconnected from this {@code
-   * FluttterActivity} at an unusual time, preventing this {@code FlutterActivity} from correctly
+   * FlutterActivity} at an unusual time, preventing this {@code FlutterActivity} from correctly
    * managing the relationship between the {@link io.flutter.embedding.engine.FlutterEngine} and
    * itself.
    */

shell/platform/common/client_wrapper/testing/stub_flutter_api.h

@@ -17,7 +17,7 @@ namespace testing {
 // the headers in platform/common/public/.
 
 // Linking this class into a test binary will provide dummy forwarding
-// implementantions of that C API, so that the wrapper can be tested separately
+// implementations of that C API, so that the wrapper can be tested separately
 // from the actual library.
 class StubFlutterApi {
  public:
@@ -29,7 +29,7 @@ class StubFlutterApi {
   // will be forwarded.
   static void SetTestStub(StubFlutterApi* stub);
 
-  // Returns the current stub, as last set by SetTestFluttterStub.
+  // Returns the current stub, as last set by SetTestFlutterStub.
   static StubFlutterApi* GetTestStub();
 
   virtual ~StubFlutterApi() {}

shell/platform/glfw/client_wrapper/testing/stub_flutter_glfw_api.h

@@ -16,15 +16,15 @@ namespace testing {
 // the headers in platform/glfw/public/.
 
 // Linking this class into a test binary will provide dummy forwarding
-// implementantions of that C API, so that the wrapper can be tested separately
+// implementations of that C API, so that the wrapper can be tested separately
 // from the actual library.
 class StubFlutterGlfwApi {
  public:
   // Sets |stub| as the instance to which calls to the Flutter library C APIs
   // will be forwarded.
   static void SetTestStub(StubFlutterGlfwApi* stub);
 
-  // Returns the current stub, as last set by SetTestFluttterStub.
+  // Returns the current stub, as last set by SetTestFlutterStub.
   static StubFlutterGlfwApi* GetTestStub();
 
   virtual ~StubFlutterGlfwApi() {}

shell/platform/windows/client_wrapper/testing/stub_flutter_windows_api.h

@@ -16,15 +16,15 @@ namespace testing {
 // the headers in platform/windows/public/.
 
 // Linking this class into a test binary will provide dummy forwarding
-// implementantions of that C API, so that the wrapper can be tested separately
+// implementations of that C API, so that the wrapper can be tested separately
 // from the actual library.
 class StubFlutterWindowsApi {
  public:
   // Sets |stub| as the instance to which calls to the Flutter library C APIs
   // will be forwarded.
   static void SetTestStub(StubFlutterWindowsApi* stub);
 
-  // Returns the current stub, as last set by SetTestFluttterStub.
+  // Returns the current stub, as last set by SetTestFlutterStub.
   static StubFlutterWindowsApi* GetTestStub();
 
   virtual ~StubFlutterWindowsApi() {}