Fixed https://github.com/cocos2d/cocos2d-x/issues/13248
Reason: `ScriptingCore::executeJSFunctionWithThisObj` is somehow broken in release mode.
Solution: Use `JSFunctionWrapper` to manage callbacks instead of managing JS values manually.
I also did the following in this commit:
- Correct the coding style in jsb_socketio.cpp
- Remove android.mk in the Xcode project