Fix race condition that allowed Component.getType() to return null (#4700)

This fix prevents an NPE in org.hibernate.mapping.SimpleValue.isValid() and likely elsewhere

hibernate-core/src/main/java/org/hibernate/mapping/Component.java

@@ -196,7 +196,8 @@ public class Component extends SimpleValue implements MetaAttributable, Sortable
 
 		if ( localType == null ) {
 			synchronized ( this ) {
-				if ( type == null ) {
+				localType = type;
+				if ( localType == null ) {
 					// Make sure this is sorted which is important especially for synthetic components
 					// Other components should be sorted already
 					sortProperties( true );