Reset Fullscreen Task Surface via SyncTransactionQueue

Split-screen dismisses itself on the SyncTransactionQueue to
prevent glitches/jank. The result, however, is that when one
of the split tasks gets unsplit, it becomes organized. Just
before it becomes organized, though, its windowcrop gets
updated on the sync transaction. Then onTaskAppeared gets
called. Then the sync transaction is applied once drawing
completes.

To resolve this, put the fullscreen transaction on the
syncTransactionQueue as well. In the future, everything that
shell does should probably be serialized in this way (eg.
PiP).

Bug: 169330989
Test: Open app, put it into split, expand the app to fullscreen,
      rotate device and observer no half black screen.
Change-Id: I3a7d3d8650a475b4aa4208bf6be9285e530514a0