Restrict when a window receives new Configurations.

It is possible that a window will relayout while it's being hidden,
but after the Configuration has changed. In this case, the window can
receive an updated Configuration incompatible with its settings.
Additionally, an Activity's window may relayout and receive a
Configuration during resume after its visibility has changed but
before the Configuration has been updated based on the current
AppWindowTokens.

This changelist addresses these issues by first only sending an
updated Configuration to the client if the associated AppWindowToken
is not requested to be hidden. In this case, the last reported
Configuration is returned instead. For the resume issue, we
address the race condition by making setting the visibility and
updating the configuration synchronized.

Fixes: 64916689
Test: go/wm-smoke
Test: place clock widget on launcher, launch landscape only activity,
      return to launcher, verify layout.

Change-Id: Ie07068be64120c2fdbe380d58af330372df6a1ab