Re-enable all VideoAdapterTests on DrMemory.

These bugs should've been resolved as of r6991.

BUG=3655,3671
R=henrike@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/22529004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6992 4adac7df-926f-26a2-2b94-8c16560cd09d