Fix PHP 8.5 deprecations of chr() and array iterator

Did a search for chr( and all instances outside 255 appear to be addressed.

This looks fine, let's get it in so we can get closer to a green test run.

Committed/pushed to 11.x, thanks!

catch → closed merge request !13108

the change looks backportable to 10.6

We aren't yet sure if we will have full compatibility for PHP 8.5 in Drupal 10 (our dependencies may not allow it) but I don't see the harm in backporting things like this.

Makes sense - cherry-picked to 10.6.x, thanks!

Thank you! surely 10.6 could fail to use PHP 8.5 but this changes are minimal )