Rollback to Drupal 11.

Closes #3270892

Think this could be added to the StatusTest::testStatusPage part of the system module (since that's also where the fix lives).

Hey @smustgrave, thanks for the review! I think this could be a good idea, but AFAIK, installing a profile is not as easy as installing a new module for example, unfortunatelly, we can't change the profile during the test and then get back to the default profile. In order to guarantee the new core/profiles/testing_install_profile_missing_version/testing_install_profile_missing_version.info.yml to be installed, I would have to change the profile variable. Something like protected $profile = 'testing_install_profile_missing_version';. And by doing this, all the tests executed by the StatusTest.php class, would have the same profile. After taking a look in some older tests, I found out that we usually have a new testing class for new testing profiles, like: InstallerExistingConfigNoProfileTest.php or DrupalFlushAllCachesInInstallerTest.php. What do you think?

PS: If you know someway to install a profile during the test execution, please let me know, maybe something like the do with modules:

    $profile_installer->install(['testing_install_profile_missing_version']);
    $this->drupalGet('admin/reports/status');
    $this->assertSession()->pageTextContains('Testing install missing version (testing_install_profile_missing_version)');
    $profile_installer->uninstall(['testing_install_profile_missing_version']);

What about moving the file to system module?

I think this can be done without any issues! I'll do that, thanks!