9 files declare their use of CommandTester in Zircon Profile 8

CommandTest.php in vendor/symfony/console/Tests/Command/CommandTest.php

CommandTesterTest.php in vendor/symfony/console/Tests/Tester/CommandTesterTest.php

DbCommandBaseTest.php in core/modules/system/tests/src/Kernel/Scripts/DbCommandBaseTest.php

Contains \Drupal\Tests\system\Kernel\Scripts\DbCommandBaseTest.

DbDumpCommandTest.php in core/modules/system/tests/src/Kernel/Scripts/DbDumpCommandTest.php

Contains \Drupal\Tests\system\Kernel\Scripts\DbDumpCommandTest.

DbDumpTest.php in core/modules/system/src/Tests/Update/DbDumpTest.php

Contains \Drupal\system\Tests\Update\DbDumpTest.

DbImportCommandTest.php in core/modules/system/tests/src/Kernel/Scripts/DbImportCommandTest.php

Contains \Drupal\Tests\system\Kernel\Scripts\DbImportCommandTest.

HelpCommandTest.php in vendor/symfony/console/Tests/Command/HelpCommandTest.php

ListCommandTest.php in vendor/symfony/console/Tests/Command/ListCommandTest.php

SymfonyStyleTest.php in vendor/symfony/console/Tests/Style/SymfonyStyleTest.php