MemorySanitizer uses generic (non-optimized) libvpx which is not bit exact. This may be a bug in upstream libvpx, but we're forced to disable it now as it blocks launching the MSan bot. R=stefan@webrtc.org TBR=marpan@webrtc.org BUG=3904 Review URL: https://webrtc-codereview.appspot.com/24089004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@7491 4adac7df-926f-26a2-2b94-8c16560cd09d