Issue #2946419 by vaplas, Lendude, Mile23: Entity: Convert system functional tests to phpunit

...les/aggregator/tests/src/Functional/FeedCacheTagsTest.php

...les/aggregator/tests/src/Functional/ItemCacheTagsTest.php

...ontent/tests/src/Functional/BlockContentCacheTagsTest.php

...les/comment/tests/src/Functional/CommentCacheTagsTest.php

...ts/src/Functional/Update/ContentTranslationUpdateTest.php

...modules/media/tests/src/Functional/MediaCacheTagsTest.php

core/modules/node/tests/src/Functional/NodeCacheTagsTest.php

...s/shortcut/tests/src/Functional/ShortcutCacheTagsTest.php

...les/system/src/Tests/Entity/EntityDefinitionTestTrait.php

...ystem/src/Tests/Entity/EntityWithUriCacheTagsTestBase.php

...odules/entity_test_update/src/Entity/EntityTestUpdate.php

...m/tests/src/Functional/Entity/EntityCacheTagsTestBase.php

...les/system/tests/src/Functional/Entity/EntityFormTest.php

...tests/src/Functional/Entity/EntityTranslationFormTest.php

.../src/Functional/Entity/EntityWithUriCacheTagsTestBase.php

...rc/Functional/Entity/Traits/EntityDefinitionTestTrait.php

...Update/SqlContentEntityStorageSchemaConverterTestBase.php

.../Functional/Update/EntityUpdateAddRevisionDefaultTest.php

...Update/EntityUpdateAddRevisionTranslationAffectedTest.php

...l/Update/EntityUpdateToRevisionableAndPublishableTest.php