Fix bug in AnimateToScene

This CL fixes a bug in AnimateToScene that would happen when triggering
a transition from A => B then directly back to B => A. When this
happened, we would snap directly to B instead of snapping to A.

Bug: 315921512
Test: SceneTransitionLayoutStateTest
Flag: N/A
Change-Id: Ia38a4d87bb288a9e25d123fc91076b7518e7f7ff
2 files changed