This CL activates the newly added AVX2 support by default. The activation is done beneath a kill-switch. Beyond the above, the CL also changes an incorrect DCHECK_GT to a DCHECK_GE. Bug: webrtc:11663 Change-Id: I231ccb2f5efabf74cd8190411daa954b2b94a2a0 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/183042 Commit-Queue: Per Åhgren <peah@webrtc.org> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Reviewed-by: Sam Zackrisson <saza@webrtc.org> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/master@{#32193}