Avoid logger serialization behind shared EntityManager proxy

See spring-projectsgh-34084

spring-orm/src/main/java/org/springframework/orm/jpa/SharedEntityManagerCreator.java

@@ -186,7 +186,7 @@ public static EntityManager createSharedEntityManager(EntityManagerFactory emf,
 	@SuppressWarnings("serial")
 	private static class SharedEntityManagerInvocationHandler implements InvocationHandler, Serializable {
 
-		private final Log logger = LogFactory.getLog(getClass());
+		private static final Log logger = LogFactory.getLog(SharedEntityManagerInvocationHandler.class);
 
 		private final EntityManagerFactory targetFactory;