HHH-18885 Introduce DelayedOperation.getAddedEntry() for maps

Extra lazy maps need to persist the added entry (key and value), not the
added value.
Let PersistentMap.AbstractMapValueDelayedOperation return the added
entry so
OneToManyPersister.writeIndex() can execute the queued operation.

Author: gtoison

hibernate-core/src/main/java/org/hibernate/collection/spi/AbstractPersistentCollection.java

@@ -849,7 +849,8 @@ public final Iterator<E> queuedAdditionIterator() {
 
 				@Override
 				public E next() {
-					return operationQueue.get( index++ ).getAddedInstance();
+					//noinspection unchecked
+					return (E) operationQueue.get( index++ ).getAddedEntry();
 				}
 
 				@Override
@@ -1204,6 +1205,10 @@ protected interface DelayedOperation<E> {
 		void operate();
 
 		E getAddedInstance();
+		
+		default Object getAddedEntry() {
+			return getAddedInstance();
+		}
 
 		E getOrphan();
 	}

hibernate-core/src/main/java/org/hibernate/collection/spi/PersistentMap.java

@@ -528,6 +528,11 @@ protected AbstractMapValueDelayedOperation(K index, E addedValue, E orphan) {
 		protected final K getIndex() {
 			return index;
 		}
+		
+		@Override
+		public Object getAddedEntry() {
+			return Map.entry( getIndex(), getAddedInstance() );
+		}
 	}
 
 	final class Put extends AbstractMapValueDelayedOperation {