- fix handling of undefined for non-externref tables
- add test for non-nullable ref table

Bug: v8:7748
Change-Id: I3f0f3aa68eb43208aea84cb8f21b37a539e14d26
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3862206
Commit-Queue: Matthias Liedtke <mliedtke@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82836}