Revert of [regexp] Create property on result for each named capture (patchset #9 id:160001 of https://codereview.chromium.org/2630233003/ )

Reason for revert:
Some heap tests are broken leading to failures on nosnap builds:

https://build.chromium.org/p/client.v8.ports/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20nosnap%20-%20debug/builds/3677

Reverting again until tests are fixed to keep bots green.

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"
>
> https://tc39.github.io/proposal-regexp-named-groups/
>
> BUG=v8:5437
>
> Review-Url: https://codereview.chromium.org/2630233003
> Cr-Original-Original-Commit-Position: refs/heads/master@{#42532}
> Committed: https://chromium.googlesource.com/v8/v8/+/70000946eb2a9155679528702a766219a1fcf154
> Review-Url: https://codereview.chromium.org/2630233003
> Cr-Original-Commit-Position: refs/heads/master@{#42570}
> Committed: https://chromium.googlesource.com/v8/v8/+/ee94fa11ed63477393c6534c352ebac6e502396c
> Review-Url: https://codereview.chromium.org/2630233003
> Cr-Commit-Position: refs/heads/master@{#42676}
> Committed: https://chromium.googlesource.com/v8/v8/+/8bf52534f6bf86821a1589dcbcb7335052c1f94f

TBR=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/2654233002
Cr-Commit-Position: refs/heads/master@{#42681}