JS: Address comments

Author: asger-semmle

javascript/ql/src/semmle/javascript/Stmt.qll

@@ -823,7 +823,9 @@ abstract class EnhancedForLoop extends LoopStmt {
    * expression in this `for`-`in` or `for`-`of` loop.
    */
   Expr getLValue() {
-    result = getIteratorExpr() or
+    result = getIterator() and
+    (result instanceof BindingPattern or result instanceof PropAccess)
+    or
     result = getIterator().(DeclStmt).getADecl().getBindingPattern()
   }
 

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

@@ -1118,7 +1118,8 @@ module DataFlow {
   }
 
   /**
-   * Gets the data flow node corresponding the given l-value expression.
+   * Gets the data flow node corresponding the given l-value expression, if
+   * such a node exists.
    *
    * This differs from `DataFlow::valueNode()`, which represents the value
    * _before_ the l-value is assigned to, whereas `DataFlow::lvalueNode()`