Merge "Add support for multi tracks in WriterTest and ListenerTest" am: 0eb4ef2828 am: 62739ebed6 am: 612623f930

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/1299384

Change-Id: If50039a260e71b30cb599d5c9244c116e5f6fa62