Make sure launcher side can animate divider

Fix divider target should pass to remote animation runner and add
mIsDividerRemoteAnimating flag to eusure launcher side controlling
the divider surface and shell side do not controll until remote
animation finished.

Fix: 211822565
Test: manual
Test: pass existing tests
Change-Id: Ie69e19feb90423a8b87351b645a5eefeead16f8a