Fix SessionEventListenerManager serialization issue

Author: dreab8

hibernate-core/src/main/java/org/hibernate/internal/AbstractSharedSessionContract.java

@@ -1183,6 +1183,7 @@ private void readObject(ObjectInputStream ois) throws IOException, ClassNotFound
 		// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 		// Step 1 :: read back non-transient state...
 		ois.defaultReadObject();
+		sessionEventsManager = new SessionEventListenerManagerImpl();
 
 		// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 		// Step 2 :: read back transient state...