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

@@ -874,7 +874,7 @@ public final Iterator<E> queuedAdditionIterator() {
 
 				@Override
 				public E next() {
-					return operationQueue.get( index++ ).getAddedInstance();
+					return operationQueue.get( index++ ).getAddedEntry();
 				}
 
 				@Override
@@ -1248,6 +1248,10 @@ protected interface DelayedOperation<E> {
 		void operate();
 
 		E getAddedInstance();
+		
+		default E getAddedEntry() {
+			return getAddedInstance();
+		}
 
 		E getOrphan();
 	}

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

@@ -539,6 +539,12 @@ protected AbstractMapValueDelayedOperation(K index, E addedValue, E orphan) {
 		protected final K getIndex() {
 			return index;
 		}
+		
+		@Override
+		public E getAddedEntry() {
+			// The (E) cast is very hacky because E is not Map.Entry but we need it to conform to PersistentCollection.queuedAdditionIterator()
+			return (E) Map.entry( getIndex(), getAddedInstance() );
+		}
 	}
 
 	final class Put extends AbstractMapValueDelayedOperation {