Commit contained wrong assert and was missing call to the runtime system for MUL.

TBR=ager@chromium.org
Review URL: http://codereview.chromium.org/6338019

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6506 ce2b1a6d-e550-0410-aec6-3dcde31c8c00