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

tests/language/named_parameters9_negative_test.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.
-// Dart test program for testing named parameters.
-
-
-class NamedParameters9NegativeTest {
-
-  static int f(a [b = 42]) => b;  // Missing comma.
-
-  static testMain() {
-    try {
-      f(10, 25);
-    } catch (e) {
-      // This is a negative test that should not compile.
-      // If it runs due to a bug, catch and ignore exceptions.
-    }
-  }
-}
-
-main() {
-  NamedParameters9NegativeTest.testMain();
-}