Teach JankTracker about new swap behaviors

Bug: 30440166

If we are using HWC2, there's a change in timing
when in triple buffering with the pipelined offsets.
This changes JankTracker to recognize that and silently
erase that from the total duration

Change-Id: Ib1fd4209070f17dbd2baed707c8cf73fb11c3cf2