audio: Allow stopping a StreamWorker from the looping thread am: 48d3115614 am: 33b5a6d8b4 am: 8883713e20 am: 783ebc4737

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2199344

Change-Id: Iab987590a96c09d98d0bffe714c6d0f8f0032b40
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>