Apply "most-recent" delivery policy to certain broadcasts.

Applying the policy to VOLUME_CHANGED_ACTION and
STREAM_DEVICES_CHANGED_ACTION broadcasts so that when dispatching
these broadcasts, we can discard any older broadcasts waiting
to be delivered and deliver only the most recent to the receivers.

Bug: 255532206
Bug: 256596007
Test: atest ./tests/tests/media/audio/src/android/media/audio/cts/AudioManagerTest.java
Change-Id: I502c8750c284e1e6ad5105b643a50d83752d86ac