frog: improve errors with named param (bug 507)

tests/language/src/NamedParameters10NegativeTest.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.
+
+// This test is very similar to NamedParameters3NegativeTest, but exersizes a
+// different corner case in the frog compiler. frog wasn't detecting unused
+// named arguments when no other arguments were expected. So, this test
+// purposely passes the exact number of positional parameters 
+
+int test(int a) {
+  return a;
+}
+
+main() {
+  try {
+    test(10, x:99);  // 1 positional arg, as expected. Param x does not exist.
+  } catch (var e) {
+    // This is a negative test that should not compile.
+    // If it runs due to a bug, catch and ignore exceptions.
+  }
+}