Refactor unit tests for the base library to use GTest.

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

Review URL: https://codereview.chromium.org/448603002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22911 ce2b1a6d-e550-0410-aec6-3dcde31c8c00