Release SurfaceView surface if viewrootimpl surface is not valid

When the window visiblity changes, SurfaceView gets notified to
release its surface. If an app relayout happens before this
notification, the ViewRootImpl surface will be null and the
SurfaceView will not release it surface.

Fixes: 158469622
Test: go/wm-smoke
Test: repro steps from bug
Test: play with SurfaceView apps
Change-Id: Ia4d5948fd229b2c77700c91691b54561d84290bb