R=ager@chromium.org
BUG=none
TEST=unboxed-double-arrays.js

Review URL: http://codereview.chromium.org/7460008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8690 ce2b1a6d-e550-0410-aec6-3dcde31c8c00