Also make sure that the appropriate functions are inlined properly
(using V8_INLINE instead of inline to enforce it even with GCC),
and improve the HashIsOkish unittest.

TEST=unittests
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/635733002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24427 ce2b1a6d-e550-0410-aec6-3dcde31c8c00