Don't preserve a11y focus in hierarchy state.

This change rolls back functionality added in ag/747748.
The idea was to restore accessibility focus on
configuration changes, but the restoration was happening
too early, which caused ViewRootImpl and the View to
disagree about accessibility focus. This confusion makes
some views unreachable by swiping after a configuration
change.

Bug: 30042251
Change-Id: Iae32b5425a1e7de9a8f5be965feb912fd2d9a0bb