Original CL description:
> Create internal fields on global proxy objects
>
> BUG=v8:5588
> R=verwaest@chromium.org

BUG=v8:5588
TBR=verwaest@chromium.org

Review-Url: https://codereview.chromium.org/2472573004
Cr-Commit-Position: refs/heads/master@{#40705}