#1869562 by fago, berdir, dawehner: Avoid instantiating EntityNG field value objects by default.

core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php

core/lib/Drupal/Core/Config/Schema/Element.php

core/lib/Drupal/Core/Config/Schema/Mapping.php

core/lib/Drupal/Core/Config/Schema/Sequence.php

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

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

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

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

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

core/lib/Drupal/Core/Entity/Field/FieldInterface.php

core/lib/Drupal/Core/Entity/Field/FieldItemBase.php

core/lib/Drupal/Core/Entity/Field/FieldItemInterface.php

...lib/Drupal/Core/Entity/Field/Type/EntityReferenceItem.php

core/lib/Drupal/Core/Entity/Field/Type/EntityTranslation.php

core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php

core/lib/Drupal/Core/Entity/Field/Type/Field.php

core/lib/Drupal/Core/Entity/Field/Type/LanguageItem.php

core/lib/Drupal/Core/Plugin/Context/Context.php

...lugin/Validation/Constraint/BundleConstraintValidator.php

...n/Validation/Constraint/EntityTypeConstraintValidator.php