Merge "VideoTrackTranscoderTests: start thread pool" into main am: 42e9c451a7 am: 986e31d931 am: 08076c6b8d

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/2904272

Change-Id: Id9c6a1bfefbdad88068a0d560eba1c5c78d02a7e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>