Switch JankTracker to FrameInfo::duration()

Fixes: 27533462

FrameInfo::duration() will remove time spent waiting
in the queue from the duration. This is desired because
that time is otherwise accounted for by the previous frame,
so we don't want to double count it.

This shows up mostly in TestSceneRunner & shadowgrid2
due to a combination of slow frame times and continous rendering.

Change-Id: I27c42d5c24d266de4ada8ea00ec9164d518754f8