[Android] Memory leak on JmeSurfaceView

[pavly-gerges]

According to this thread, there is a memory leak, the test was conducted on JmeSurfaceView.

A proposed blind solution was to add JmeSystemDelegate.setView(null) within the JmeSurfaceView#destroy(), which surprisingly was already on AndroidHarness, I think this is a real memory leak that is specific to JmeSurfaceView.