Make sure to cleanup views that couldn't be added

ie: due to BadTokenException or InvalidDisplayException

Previously, only views that were already in the viewhierarchy
before attempted to be re-added would be removed. This makes
sure if the view was newly added, it'll also be removed.
This prevents a memory leak of views.

Test: manually show and cancel multiple toasts,
check the hierachy viewer that no Toast views remain
Fixes: 234694098

Change-Id: I06bbae70c277d0615753edc9ec0a8e7439ad7020