This reverts commit be12fefa4b7d224e9f39275a6bb4fab01b8bae3b
and commit 057c1c4034ba5b9bf360c5c1f600ebc6d0718c3a.
Also, the mismatch between the avx version and the
c version has been fixed.
BUG=https://bugs.chromium.org/p/webm/issues/detail?id=1168
For a rt encode using 1080p@60fps material, up to 11% performance
improvement overall was seen.
Change-Id: Icd1f216209ebc6fc0b8da885f32f356fa4355ed0