HHH-8703 - Remove NonFlushedChanges api
(cherry picked from commit d6fa2b286447e17f926906cf6867e508d6a5b87e)

Conflicts:

	hibernate-core/src/main/java/org/hibernate/engine/spi/NonFlushedChanges.java
	hibernate-core/src/main/java/org/hibernate/internal/NonFlushedChangesImpl.java
	hibernate-core/src/test/java/org/hibernate/test/nonflushedchanges/CreateTest.java
	hibernate-core/src/test/java/org/hibernate/test/nonflushedchanges/MergeTest.java
	hibernate-core/src/test/java/org/hibernate/test/nonflushedchanges/SaveOrUpdateTest.java
HHH-8703 Remove need to support EntityKey de-serialization without having access to a SessionFactory
(cherry picked from commit 9a3b1417c63662c5fbd212ae615c7d5168b3b7c4)

Conflicts:

	hibernate-core/src/main/java/org/hibernate/persister/entity/EntityPersister.java