Example performance: 1.8% bit rate savings using
the AQ test mode aq-mode=4 :
./aomenc --codec=av1 --ivf --tile-columns=1 --tile-rows=1 \
                 --kf-max-dist=1000 --kf-min-dist=1000 --cpu-used=0 \
                 --passes=1 --threads=1 --lag-in-frames=0 \
                 --end-usage=q --limit=600 --cq-level=42 \
                 --aq-mode=4 --error-resilient=1 out.bits FourPeople_1280x720_60.y4m

Change-Id: Iba01cf2732a57f3c27481ac2a3c8fc37bb9e5533