Fixed MenuWrapper memory leak

Issue is the same as was with old View.setTag(id, tag) implementation(was discussed [here](http://stackoverflow.com/a/7145210/87383) and [here](https://code.google.com/p/android/issues/detail?id=18273)).

So you have to clean mNativeMap to fit real menu.

P.S. I think it's corner case because it's not a very common case when you have pointers to(or from) menu items from activity, fragments, etc...