Set resizing to false if no fling animation

While dobble taps gesture, it may moves the divider bar
meanwhile, it means we set resizing to true but didn't set it back
to false because position is same and no animation. We should set
resizing to false for such status.

Also fix such bug on legacy split screen. We call stopDragging with
no animation in some status, it should call setResizing false too.

Fix: 192635568
Test: Eanble stage split with any two apps and dobble tap on divider
      many times.
Change-Id: I170e3de347cc5fc19eaa1cd3d64922b2b631e550