Fix intl402/*/ignore-invalid-unicode-ext-values
Add tests for other valid/invalid -u- ext values.

Bug: v8:7481
Change-Id: I429effd071bb03599a1e767bb2a9e9918a91b850
Reviewed-on: https://chromium-review.googlesource.com/c/1351307
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58173}