6 files declare their use of EntityTestMul in Zircon Profile 8

ContentEntityCloneTest.php in core/modules/system/src/Tests/Entity/ContentEntityCloneTest.php

Contains \Drupal\system\Tests\Entity\ContentEntityCloneTest.

EntityReferenceRelationshipTest.php in core/modules/field/src/Tests/EntityReference/Views/EntityReferenceRelationshipTest.php

Contains \Drupal\field\Tests\EntityReference\Views\EntityReferenceRelationshipTest.

EntityUnitTest.php in core/tests/Drupal/Tests/Core/Entity/EntityUnitTest.php

Contains \Drupal\Tests\Core\Entity\EntityUnitTest.

EntityViewsDataTest.php in core/modules/views/tests/src/Unit/EntityViewsDataTest.php

Contains \Drupal\Tests\views\Unit\EntityViewsDataTest.

QueryGroupByTest.php in core/modules/views/src/Tests/QueryGroupByTest.php

Contains \Drupal\views\Tests\QueryGroupByTest.

RouteProviderTest.php in core/tests/Drupal/KernelTests/Core/Entity/RouteProviderTest.php

Contains \Drupal\KernelTests\Core\Entity\RouteProviderTest.