Merge "stagefright: notify async release complete" into rvc-dev am: 3244d0db am: d0ac7b8a am: 0eba4cf5

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/11795217

Change-Id: Ice0671a610de22a6d101baa07c5feb06aa11bab9