Pass VM instead of JSGlobalObject to RegExp constructor.
<https://webkit.org/b/122113> Reviewed by Darin Adler. RegExps don't need anything from the global object during their construction and only use it to get to the VM. Reduce loads by simply passing the VM around instead. JSC release binary size -= 120 bytes(!) git-svn-id: http://svn.webkit.org/repository/webkit/trunk@156668 268f45cc-cd09-0410-ab3c-d52691b4dbfc