module_load_install() removed in Drupal 10

My merge request may not be needed. It may just need that line removed. It appears that the next line in the code is effectively the same thing, but I haven't tested it.

Hah, I should've checked the issue list before releasing rc1 shouldn't I lol. As this issue just relates to the test suite this doesn't affect anything there though, so rc1 is still fine. You're right that \Drupal::moduleHandler() and \Drupal::service('module_handler') are doing exactly the same thing - they both get the module_handler from the container, so we only need one of them.