GH-543 'oval.getInstance()' can return null

Author: thurka

visualvm/heapviewer/src/org/graalvm/visualvm/heapviewer/java/impl/HeapPatterns.java

@@ -45,7 +45,7 @@ static PathToGCRootPlugin.SkipNode processGCRootReference(ObjectFieldValue refer
                 break;
             }
             ObjectFieldValue oval = getValueOfField(path, ref.getField());
-            if (oval == null || !oval.getInstance().equals(i)) {
+            if (oval == null || !i.equals(oval.getInstance())) {
                 break;
             }
             ref = oval;