Merge "mediaserver: add more hwbinder threads" into rvc-dev am: 2038329c am: 90dcc0b7 am: 331a69f0

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/12046706

Change-Id: I009c7e179b0c8e5cdb3936d1ac32c4782b96d6b7