Add a non-blast mode to sync-engine

This adds a "method" to sync-engine where an app just draws
internally and reports (no sync).

The transition system can then use this to implement its own
screenshot-based sync mechanism. For now, this uses legacy logic
around "changeTransition" to decide which levels to take
screenshots at (since screenshots are slow).

This also adds a per-window method override to handle situations
where one window/sub-hierarchy needs to use or not-use a
method (specifically, seamless-rotation needs BLAST even if
the rest of the transitions are screenshot).

Bug: 242056267
Test: atest TransitionTests SyncEngineTests
Change-Id: Iee6ee85bafb8967e2e1e662cd3275fba1efbbdea