Rename COMPILER_TEST to TARGET_TARGET.

The name COMPILER_TEST is misleading here.

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/465913002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23070 ce2b1a6d-e550-0410-aec6-3dcde31c8c00