Issue #3407793 by mstrelan: Add declare(strict_types=1) to all miscellaneous test classes

core/modules/field/tests/src/Functional/NestedFormTest.php

core/modules/system/src/Tests/Routing/MockAliasManager.php

core/modules/system/src/Tests/Routing/MockRouteProvider.php

core/phpcs.xml.dist

...tests/Drupal/TestSite/Commands/TestSiteInstallCommand.php

.../Drupal/TestSite/Commands/TestSiteReleaseLocksCommand.php

...ests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php

...sts/Drupal/TestSite/Commands/TestSiteUserLoginCommand.php

core/tests/Drupal/TestSite/TestPreinstallInterface.php

core/tests/Drupal/TestSite/TestSetupInterface.php

core/tests/Drupal/TestSite/TestSiteApplication.php

core/tests/Drupal/TestSite/TestSiteInstallTestScript.php

...Drupal/TestSite/TestSiteMultilingualInstallTestScript.php

...ests/Drupal/TestSite/TestSiteOliveroInstallTestScript.php

...Drupal/TestTools/Comparator/MarkupInterfaceComparator.php

...ests/Drupal/TestTools/Extension/RequiresComposerTrait.php

core/tests/Drupal/TestTools/Extension/SchemaInspector.php

...sts/Drupal/TestTools/PhpUnitCompatibility/ClassWriter.php

.../PhpUnitCompatibility/PhpUnit9/TestCompatibilityTrait.php

...s/Drupal/TestTools/PhpUnitCompatibility/RunnerVersion.php