Reason for revert:
Breaks arm64.
Original issue's description:
> [regexp] Store named captures on the regexp result
>
> This implements storing named captures on the regexp result object.
> For instance, /(?<a>.)/u.exec("b") will return a result such that:
>
> result.group.a // "b"
>
> The spec proposal is not yet final, so this may still change in the future.
>
> BUG=v8:5437
>
> Review-Url: https://codereview.chromium.org/2630233003
> Cr-Original-Commit-Position: refs/heads/master@{#42532}
> Committed: 70000946eb
> Review-Url: https://codereview.chromium.org/2630233003
> Cr-Commit-Position: refs/heads/master@{#42570}
> Committed: ee94fa11edTBR=yangguo@chromium.org,littledan@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5437
Review-Url: https://codereview.chromium.org/2639403008
Cr-Commit-Position: refs/heads/master@{#42577}
50e0fe29bb