Resize mRemoteTargetHandles when RecentsAnimationStarts

* TopTaskTracker gets updated too late after we've exited
split screen so we can't use that to determine how many
RemoteTargetHandles to use
* We default to 2, and then scale it down to 1. Because we
modify the array holding the handles directly, it should
also get updated in AbsSwipeUpHandler
* Temporary solution to stop setting up RecentsView if we detect that
TopTaskTracker has incorrect data and re-setup when we get
onRecentsAnimationStart()

Test: Tested quickswitch in gestural and recents button
double tap in button nav.
Bug: 236226779
Flag: none

Change-Id: I1bae7aed1f8712ddd1bf496acfcb851c0e32a115