audio: Allow stopping a StreamWorker from the looping thread am: 48d3115614 am: 33b5a6d8b4

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

Change-Id: Ie6ccc3aa54a7614184784b3433d7e1c4044d7115
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>