Deliver deferred broadcasts if nothing else is pending

There's no point in adding meaningless latency to overall broadcast
handling, so we now ignore deferral policy when no "ordinary" broadcasts
are pending delivery.

Fixes: 127965049
Test: manual
Test: atest/ActivityTests
Change-Id: Ied8fa2ca5637ccb0dcbbbd9daaec514406ba504a
1 file changed