Prevent restoring split selection state for fallback overview

* Add flag to explicitly not restore
OVERVIEW_SPLIT_SELECT
* FallbackRecentsView then resets state in
RecentsView if our endState is ever not split selection

Fixes: 253178217
Test: Used launcher developer option to
force use separate recents activity. Tested w/
3 button nav + gesture.

Change-Id: I26c9994bf853e9a005300a02aa143991958fc461