SurfaceView: Destroy SurfaceControl from RenderThread

Currently there is a race where the UI thread can destroy
the SurfaceControl (free the C++ object) while the RenderThread
still has pending operations on it. To fix have the positionLost callback handle the destruction.

Bug: 139111930
Bug: 136808018
Test: go/wm-smoke
Change-Id: Id5225e1e47046d928f8298de38ff61662debe360