Merge "stagefright: notify async release complete" into rvc-dev am: 3244d0db9d am: cb2a90941c

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

Change-Id: I5dd66a9a11601bb284d4e7e2dea494f28031d88e