Revert "make Intl non-enumerable"

This reverts commit 327355efe28995f5d91aadb54c71ea1d292c8428.

TBR=svenpanne@chromium.org,dcarney@chromium.org

Review URL: https://codereview.chromium.org/22893026

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16204 ce2b1a6d-e550-0410-aec6-3dcde31c8c00