Fixed tests so they do indeed confirm that values on optional named parameters are not allowed. Add…

lib/compiler/implementation/scanner/partial_parser.dart

 // Copyright (c) 2011, 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.
 
 class PartialParser extends Parser {
   PartialParser(Listener listener) : super(listener);
 
   Token parseClassBody(Token token) => skipClassBody(token);
 
   Token fullParseClassBody(Token token) => super.parseClassBody(token);
@@ skipping 72 matching lines @@
       expectSemicolon(token);
     } else {
       token = skipBlock(token);
     }
     // There is no "skipped function body event", so we use
     // handleNoFunctionBody instead.
     listener.handleNoFunctionBody(token);
     return token;
   }
 
-  Token parseFormalParameters(Token token) => skipFormals(token);
+  Token parseFormalParameters(Token token, [bool allowValuesForNamedOptionalParams = true]) => skipFormals(token);
 
   Token skipFormals(Token token) {
     listener.beginOptionalFormalParameters(token);
     if (!optional('(', token)) {
       if (optional(';', token)) {
         listener.recoverableError("expected '('", token: token);
         return token;
       }
       return listener.unexpected(token);
     }
     BeginGroupToken beginGroupToken = token;
     Token endToken = beginGroupToken.endGroup;
     listener.endFormalParameters(0, token, endToken);
     return endToken.next;
   }
 }