Always apply postDrawTransaction started during sync

ViewRootImpl tracks the full lifetime of all sync buffers.
This means its important to apply all transactions which have
a sync buffer or ViewRootImpl will not draw new frames.

This CL makes it so that even if a window is no-longer in a
sync-set, the post-draw transaction will be applied as long
as it was in a sync transaction at the time it was requested.

Bug: 183993924
Test: atest WindowUntrustedTouchTest
Change-Id: Id89d039328bd9b091d4ed78a1616bc78d1bd83fa