This CL changes the use of a ZoneList for keeping track of named captures
in a regular expression to a ZoneMap, to optimize finding the named
capture in the structure.

Bug: v8:9423
Change-Id: Id952ac8f86c1dc5d69a3b0251ff724d1509879dc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1687413
Commit-Queue: Ana Pesko <anapesko@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62601}