frameworks/base: Fix the random UI corruption

On low memory device, when a view goes to background. Its HW layer cache
will be destroyed to release memory. There is a very rare case that the
hardware render is not valid when destroy the layer, so the layer is not
destroyed and reused when the view comes to foreground. But the GL
context has changed, so the view is not rendered correctly due to its
HW layer cache. To fix this issue, destroy the layer in a safelyRun. Make
sure the layer is destroyed correctly.

Change-Id: I1c714e1d53db7353d5169e874a7cd0f527c3f67b