Re-allow suppressing onDetachedFromWindow

Bug: 17578553

Games seem to be doing this to prevent destruction of their
GL contexts, and they assume it works even if it doesn't. However,
GLSurfaceView is clunky here, so while the app is doing something
questionable we don't really offer a better way. For now revert
back to kitkat behavior.

Change-Id: Icfa9e496279b9cfa47f9bc7f6848d9313caed0d5