Reason for revert:
nisse landed a change that always disable adaptation in these tests.
Original issue's description:
> Fix flaky WebRtcVideoChannel2BaseTest.GetStats T
> This cl allows width and height of the produced encoded stream to be smaller than the configured camera resolution. This is since quality and cpu adapters may request a scaled input frame.
>
> BUG=webrtc:6990
>
> Review-Url: https://codereview.webrtc.org/2634273002
> Cr-Commit-Position: refs/heads/master@{#16118}
> Committed: 311a64ccf5
TBR=sprang@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6990
Review-Url: https://codereview.webrtc.org/2639573002
Cr-Commit-Position: refs/heads/master@{#16120}