Merge "Add support for multi tracks in WriterTest and ListenerTest" am: 0eb4ef2828 am: 62739ebed6 am: 612623f930 am: f99397effd

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

Change-Id: I8c15700502dd75fa0fe8ddd7573ce4b463dbc388