Add getXPathNodeName to the Node interface

A default implementation is available in AbstractNode
to preserve compatibility with the previous way, which
used Object.toString.

Fixes #569

pmd-javascript/src/main/java/net/sourceforge/pmd/lang/ecmascript/ast/AbstractEcmascriptNode.java

@@ -70,6 +70,12 @@ public abstract class AbstractEcmascriptNode<T extends AstNode> extends Abstract
 
     @Override
     public String toString() {
+        return getXPathNodeName();
+    }
+
+
+    @Override
+    public String getXPathNodeName() {
         return node.shortName();
     }
 }

pmd-javascript/src/main/java/net/sourceforge/pmd/lang/ecmascript/ast/DumpFacade.java

@@ -49,7 +49,7 @@ public class DumpFacade {
         writer.print(prefix);
 
         // 2) JJT Name of the Node
-        writer.print(node.toString());
+        writer.print(node.getXPathNodeName());
 
         //
         // If there are any additional details, then: