This avoids attempting to redefine function.arguments with a different
value than the current one. function.arguments returns a new copy on
each invocation.

R=lrn@chromium.org
BUG=v8:1447
TEST=mjsunit/regress/regress-1447.js

Review URL: http://codereview.chromium.org/7044104

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8258 ce2b1a6d-e550-0410-aec6-3dcde31c8c00