Removing W3C conformance tests after move to web-platform-tests.

BUG=webrtc:3455
R=kjellander@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/14809004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6563 4adac7df-926f-26a2-2b94-8c16560cd09d