JS: Add getALocalUse

javascript/ql/src/semmle/javascript/dataflow/Sources.qll

@@ -52,6 +52,11 @@ class SourceNode extends DataFlow::Node {
    */
   predicate flowsToExpr(Expr sink) { flowsTo(DataFlow::valueNode(sink)) }
 
+  /**
+   * Gets a node into which data may flow from this node in zero or more local steps.
+   */
+  DataFlow::Node getALocalUse() { flowsTo(result) }
+
   /**
    * Gets a reference (read or write) of property `propName` on this node.
    */