Revert r8577 "Collapse AudioEncoderDecoderIsacRed into ..."

Some of the build bots seems to have reacted to this change.

TBR=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/42169004

Cr-Original-Commit-Position: refs/heads/master@{#8578}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: bcef431902ad4addbd8fce8b1289b35cdfec1416
7 files changed