Issue #2346421 by yched: Fixed WTF with getTargetEntityId() / getBundle().

core/lib/Drupal/Core/Entity/EntityManager.php

core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php

core/lib/Drupal/Core/Field/BaseFieldDefinition.php

core/lib/Drupal/Core/Field/FieldConfigBase.php

core/lib/Drupal/Core/Field/FieldConfigInterface.php

core/lib/Drupal/Core/Field/FieldDefinitionInterface.php

...lib/Drupal/Core/Field/FieldStorageDefinitionInterface.php

core/modules/config_translation/src/ConfigFieldMapper.php

core/modules/system/src/Tests/Entity/EntityFieldTest.php

...ests/modules/entity_schema_test/entity_schema_test.module