Remove a disabled test.

ConstrainsSetCodecsAccordingToEncoderConfig has been removed from
webrtcvideoengine_unittest.cc, removing this one as well.

BUG=1788
R=wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/21949004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6789 4adac7df-926f-26a2-2b94-8c16560cd09d