Revert of [test] Move test262-es6 into test262. (patchset #2 id:20001 of https://codereview.chromium.org/1215303008/)

Reason for revert:
[Sheriff] Breaks test262 on mac

Original issue's description:
> [test] Move test262-es6 into test262.
>
> BUG=v8:4254
> LOG=n
>
> Committed: https://crrev.com/aaa457b26f6c0f624cf5887e60dc497f6dccabae
> Cr-Commit-Position: refs/heads/master@{#29479}

TBR=rossberg@chromium.org,arv@chromium.org,littledan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4254

Review URL: https://codereview.chromium.org/1227503002

Cr-Commit-Position: refs/heads/master@{#29483}