Update flush test to flush audio too and wait for pause

Flush audio and video (instead of just video) and wait for the pause to occur before
flushing, seeking and continuing playback.

Bug: 234328838
Test: atest android.media.decoder.cts.DecoderTest#testTunneledAccurateVideoFlushAvc
Change-Id: Ib983dc7fdf8ae39cb172091b2d8969da9fbcd457
2 files changed