R=arv@chromium.org
BUG=
TEST=error-tostring.js

Review URL: https://chromiumcodereview.appspot.com/10388208

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12151 ce2b1a6d-e550-0410-aec6-3dcde31c8c00