Composer: update test dependencies

Selectively update test dependencies to get us onto versions compatible with PHP 8.4.

Refs:
* https://github.com/antecedent/patchwork/releases/tag/2.2.0
* https://github.com/antecedent/patchwork/releases/tag/2.2.1
* https://github.com/Brain-WP/BrainMonkey/releases/tag/2.6.2
* https://github.com/Yoast/PHPUnit-Polyfills/releases/tag/1.1.2
* https://github.com/sebastianbergmann/phpunit/blob/8.5.40/ChangeLog-8.5.md