This CL adjusts the filter adaptation behavior to better handle
reverberant environments and environments with poor SNR.
It furthermore updates the unittests to handle the reduced adaptation
speed.
Bug: webrtc:8661
Change-Id: I5f1b5a4a34b333bd6c643ed3727899d0838dbf90
Reviewed-on: https://webrtc-review.googlesource.com/34184
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21323}
019008bd93