Merge "VTS: add AdaptiveBitrate test for video encoders" into rvc-dev am: e57d67733d am: bfdeba66fe am: c8531316b2 am: 8aee9cbfb1 am: 0abe19dd2f

Change-Id: Ifef470b3681f6d7d0d851789efdf02d4e888aacd