The property was removed in 6c717734,
creates now a dynamic property in the ResourceLoaderTestModule class,
that is deprecated in php8.2
1) MediaWiki\Tests\ResourceLoader\StartUpModuleTest::testGetModuleRegistrations
with data set #13 (array('ES6-only module',
array(array('ResourceLoaderTestModule', true)),
'\nmw.loader.addSource({\n ...]\n]);'))
Creation of dynamic property ResourceLoaderTestModule::$es6 is
deprecated
/workspace/src/tests/phpunit/ResourceLoaderTestCase.php:135
Follow-Up: Ib6263ce3ffd11af5e501de8857f3e48a248c6210
Change-Id: I6abd119fac7f660b74978ebb01172d652223d84e
e058b70b12