Reason for revert:
The tests in the CL are failing on the bots in the Webrtc Waterfall (allthough they did not fail on the commit bots). I will therefore revise and reland the test.
Original issue's description:
> Added a bitexactness test for the echo canceller in the audio processing module.
>
> BUG=webrtc:5337
>
> Committed: https://crrev.com/7c448e1a384224aa16a21715e83574f3f553b730
> Cr-Commit-Position: refs/heads/master@{#12068}
TBR=henrik.lundin@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5337
Review URL: https://codereview.webrtc.org/1824583003
Cr-Commit-Position: refs/heads/master@{#12072}
f26f98b29c