Accessibility focus should not clear selection when taken away.

1. Currently accessibility focus removal was clearing the selection
   in the view - in particular the accessibility cursor position
   which in the TextView case is the selection. This leads to a
   scenario where the selection may be cleared when the app does
   not explect. Further, the selection should not be cleared
   since the user can be say several pages in the content and
   removing and putting back accessibility focus would cause a
   tedious traversal to get to the previous position.

bug:6469840

Change-Id: Iba3c01600fa2c9c39f99085a5fbc4328aa539ea8