This change adds ES5 15.2.3.9 Object.freeze and 
15.2.3.12 Object.isFrozen

Review URL: http://codereview.chromium.org/2944016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5055 ce2b1a6d-e550-0410-aec6-3dcde31c8c00