According to https://www.w3.org/TR/html5/obsolete.html#dom-document-all,
comparisons of document.all to other values such as strings or objects,
are unaffected. In fact document.all only gets special treatment in
comparisons with null or undefined according to HTML. Especially setting
the undetectable doesn't make two distinct JSReceivers equal.

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1774273002

Cr-Commit-Position: refs/heads/master@{#34608}