Revert "Initial import of unittests using GTest/GMock."

This reverts commit r22847 and r22848. Isolate initialization/shutdown
still broken (so certain debug builds just crash), and our compiler flags
do not work with other Google projects (i.e. GTest/GMock).

TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/438243003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22855 ce2b1a6d-e550-0410-aec6-3dcde31c8c00