Fix VariableDefinitions.endToken for formal parameters.

sdk/lib/_internal/compiler/implementation/tree/nodes.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of tree;
 
 abstract class Visitor<R> {
   const Visitor();
 
   R visitNode(Node node);
@@ skipping 1074 matching lines @@
   }
 
   Token getBeginToken() {
     var token = firstBeginToken(modifiers, type);
     if (token == null) {
       token = definitions.getBeginToken();
     }
     return token;
   }
 
-  Token getEndToken() => endToken;
+  Token getEndToken() {
+    if (endToken == null) {
+      return definitions.getEndToken();
+    }
+    return endToken;
+  }
 }
 
 abstract class Loop extends Statement {
   Expression get condition;
   final Statement body;
 
   Loop(this.body);
 
   bool isValidContinueTarget() => true;
 }
@@ skipping 953 matching lines @@
  * argument).
  *
  * TODO(ahe): This method is controversial, the team needs to discuss
  * if top-level methods are acceptable and what naming conventions to
  * use.
  */
 initializerDo(Node node, f(Node node)) {
   SendSet send = node.asSendSet();
   if (send != null) return f(send.arguments.head);
 }