Enable -Wextra in C++ builds (#1294)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1294

X-link: https://github.com/facebook/react-native/pull/37383

Add -Wextra to the build, and fixup some more instances of -Wunused-parameter that it sufaces which were not automatically fixable.

Reviewed By: javache

Differential Revision: D45772846

fbshipit-source-id: 680498f66f2104c29a71366bf30dba8895d9baf4

java/jni/corefunctions.cpp

@@ -56,6 +56,7 @@ JNIEXPORT JNIEnv* getCurrentEnv() {
 }
 
 void logErrorMessageAndDie(const char* message) {
+  (void) message;
   VANILLAJNI_LOG_ERROR(
       "VanillaJni",
       "Aborting due to error detected in native code: %s",