Skip -pedantic for GTest as long as we -std=gnu++0x.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/457553002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22986 ce2b1a6d-e550-0410-aec6-3dcde31c8c00