Issue #2423213 by plach: Schema for newly defined entity types is never created

.../lib/Drupal/Core/Entity/EntityDefinitionUpdateManager.php

...al/Core/Entity/EntityDefinitionUpdateManagerInterface.php

...locale/src/Tests/LocaleTranslatedSchemaDefinitionTest.php

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

...es/system/src/Tests/Entity/EntityDefinitionUpdateTest.php

core/modules/system/src/Tests/Update/UpdateScriptTest.php

...dules/system/tests/modules/entity_test/entity_test.module

...em/tests/modules/entity_test/src/Entity/EntityTestNew.php