Add initial support for compiler unit tests using GTest/GMock.

TEST=compiler-unittests
BUG=v8:3489
LOG=y
R=svenpanne@chromium.org, jochen@chromium.org

Review URL: https://codereview.chromium.org/447563003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22927 ce2b1a6d-e550-0410-aec6-3dcde31c8c00