BLAST: Ensure buffers are submitted before reporting draw finished

If blast sync is not enabled abut we need to report draw finished
for the next frame, call setNextTransaction. Blast buffer queue
will process any queued up buffers and ensure the buffer is
submitted before reporting draw finished.

Test: Test no flickers with blast enabled in splitscreen
Change-Id: If7a36eb0a9a2914dd37adfd20abcbe2b5074b16a