removed webrtc_base_tests_utils from merge libs as it was breaking some builds.

BUG=N/A
R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/18469004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6177 4adac7df-926f-26a2-2b94-8c16560cd09d