Symfony\Polyfill\Intl\Icu\Collator::compare() is not implemented

It turned out that my intl free test environment had still intl installed.

Tested the patch against 11.x manually on simplytest.me (where 11.x fails without patch) . Please review

I've reverted 🐛 Lists with items containing non-ascii characters are not sorted correctly Needs review , let's fix that over there and re-commit. Marking this as duplicate.

Upstream issue: https://github.com/symfony/polyfill/issues/535