WM: Defer transactions for BLAST Surfaces too.

For switching on BLAST we are implementing deferred transactions for
compatibility. Presently the BLAST Surface is constructed by the ViewRootImpl
and so the WM has no reference to pass when using it as a barrier layer for
deferTransactionUntil. To resolve this we construct and hold a reference to
the BLAST Surface on the server side, and pass it down to the client in relayoutWindow.
We don't use the WindowStateAnimator surface directly as both the BLAST Adapter and
the WindowStateAnimator would then be setting crops on it.

Bug: 146598493
Test: Builds, existing tests pass.
Change-Id: I6513e0442f5c75f01eb8dde5f1924dd7b636163c