Reason for revert:
This causes compatibility issues, as documented in https://bugs.chromium.org/p/v8/issues/detail?id=4617#c9

Original issue's description:
> [es6] ship regexp sticky flag.
>
> R=littledan@chromium.org
> BUG=v8:4342
> LOG=Y
>
> Committed: https://crrev.com/86c2dd4042dc9ce293e004234eb094f2b51d9640
> Cr-Commit-Position: refs/heads/master@{#32826}

TBR=yangguo@chromium.org,littledan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4342
LOG=Y

Review URL: https://codereview.chromium.org/1531243002

Cr-Commit-Position: refs/heads/master@{#32932}