Avoid a run-time dispatch for tables that don't contain subtypes of
funcref.

Change-Id: I27a55c378b0a4fcd98e77f8ff45ae9972c9d095a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3644961Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Andy Wingo <wingo@igalia.com>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80648}