8 files declare their use of RunnerVersion in Drupal 8

AfterSymfonyListener.php in core/tests/Drupal/Tests/Listeners/AfterSymfonyListener.php

Listens to PHPUnit test runs.

DrupalListener.php in core/tests/Drupal/Tests/Listeners/DrupalListener.php

Listens to PHPUnit test runs.

FileFieldTestBase.php in core/modules/file/tests/src/Functional/FileFieldTestBase.php

FileFieldValidateTest.php in core/modules/file/tests/src/Functional/FileFieldValidateTest.php

HtmlOutputPrinter.php in core/tests/Drupal/Tests/Listeners/HtmlOutputPrinter.php

Defines a class for providing html output results for functional tests.

PhpunitCompatibilityTrait.php in core/tests/Drupal/Tests/PhpunitCompatibilityTrait.php

SimpletestUiPrinter.php in core/tests/Drupal/Tests/Listeners/SimpletestUiPrinter.php

Defines a class for providing html output links in the Simpletest UI.

TestSuiteBaseTest.php in core/tests/Drupal/Tests/Core/Test/TestSuiteBaseTest.php