When creating the results object for an exec call, V8 is calling into a
runtime helper once per named capture group. It can instead create that
object without any runtime calls, using existing CSA helpers. The only
additional cost of this approach is that it internalizes the capture
group names at regex compilation time, even if the script never calls
exec on that regex.

Bug: v8:6914

Change-Id: I58975b8d7aea05f8c67ae087608715099f62fc48
Reviewed-on: https://chromium-review.googlesource.com/c/1454268Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#59470}