Fix issue #5312624: Lock screen very flickery

The key thing was to fix isVisibleOrBehindKeyguardLw() so that it
wouldn't count a window as not visible if it was just currently
in the process of drawing due to an orientation change.

Also improve logic in deciding when to turn screen on to better ensure
the screen is in a stable state, in particular treating screen off
as a frozen screen and not allowing it to turn on until the
update of the screen due to any config change is done.

Change-Id: If82199f3773270b2d07f9c7de9da2dad8c7b28d7