R=rossberg@chromium.org
BUG=v8:1845
TEST=mjsunit/harmony/proxies-example-membrane

Review URL: https://chromiumcodereview.appspot.com/9365011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10632 ce2b1a6d-e550-0410-aec6-3dcde31c8c00