HHH-10554 - Fix NPE in dirty tracking generated code of bytecode enhanced @Embeddable entities

(cherry picked from commit c5104601e1)

hibernate-core/src/main/java/org/hibernate/bytecode/enhance/internal/PersistentAttributesEnhancer.java

@@ -448,7 +448,7 @@ public class PersistentAttributesEnhancer extends Enhancer {
 		// trigger track changes
 		fieldWriter.insertAfter(
 				String.format(
-								"((%2$s) %1$s).%4$s(\"%1$s\", (%3$s) this);%n" +
+								"if (%1$s != null) { ((%2$s) %1$s).%4$s(\"%1$s\", (%3$s) this); }%n" +
 								"%5$s(\"%1$s\");",
 						persistentField.getName(),
 						CompositeTracker.class.getName(),

hibernate-core/src/test/java/org/hibernate/test/bytecode/enhancement/dirty/DirtyTrackingTestTask.java

@@ -84,6 +84,9 @@ public class DirtyTrackingTestTask extends AbstractEnhancerTestTask {
 		country.setName( "Norway" );
 		EnhancerTestUtils.checkDirtyTracking( entity, "address", "address.country" );
 
+		address.setCountry( null );
+		entity.setAddress( null );
+
 	}
 
 	protected void cleanup() {