Stop writing to audio track once stop drainning is called

The stop should be stop writing to audio track, instead of
only stopping to write to the local queue.
Additionally, the audio offset is changed to be applied right
before writing to the audio track.

Test: atest DecoderTest#tunneledAudioUnderrun
      atest DecoderTest#testTunneledAudioProgressWithUnderrun
      atest DecoderTest#testTunneledAudioProgressWithPtsGaps
Bug: 294519143

Change-Id: I843889328bae093c925be6a26e91a0b5249feffe