Added mirror of gtest-parallel.

gtest-parallel is a Python script that runs gtest binaries in parallel.

R=andrew@webrtc.org, kjellander@webrtc.org, mflodman@webrtc.org
BUG=

Review URL: https://webrtc-codereview.appspot.com/11309004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6227 4adac7df-926f-26a2-2b94-8c16560cd09d