This is a reland of dd8845cd

Original change's description:
> [intl] Improve test coverage of "best fit" localeMatcher
>
> https: //docs.google.com/document/d/1cPGfiihn76yj2iAomKcspPFyLLcnk3WkCiqceBQPQyk/edit#heading=h.cc9tt7s0iwsd
> Bug: v8:7051
> Change-Id: I8c35e859062c5bdb009334dd1b725751e6df2123
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2965481
> Reviewed-by: Shu-yu Guo <syg@chromium.org>
> Commit-Queue: Frank Tang <ftang@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#75228}

Bug: v8:7051
Change-Id: I9af13b8fdf7ec3de2ac24050074d13fcdef981c7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2973648Reviewed-by: Frank Tang <ftang@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75280}