Change NotImplementedException to UnimplementedError.

tests/language/named_parameters_with_dollars_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.
 
 // Test to stress Frog's named parameter scheme.
 
 main() {
   testDollar();
   testPsycho();
 }
@@ skipping 19 matching lines @@
     fragments.add(']');
     return Strings.concatAll(fragments);
   }
   return thing.toString();
 }
 
 // Hopefully inscrutable to static analysis.
 makeTestClass(n) => [new TestClass(), new Decoy(), 'string'][n % 3];
 
 class Decoy {
-  method([a$b, b, a]) { throw const NotImplementedException(); }
-  psycho([$$$, $$, $])  { throw const NotImplementedException(); }
+  method([a$b, b, a]) { throw new UnimplementedError(); }
+  psycho([$$$, $$, $])  { throw new UnimplementedError(); }
 }
 
 testDollar() {
   Expect.equals('[]', format([]));
 
   Expect.equals('[-, -, -, -]', format(globalMethod()));
   Expect.equals('[1, 2, -, -]', format(globalMethod(a: 1, b: 2)));
   Expect.equals('[1, 2, -, -]', format(globalMethod(b: 2, a: 1)));
   Expect.equals('[-, -, 3, -]', format(globalMethod(a$b: 3)));
   Expect.equals('[-, -, -, 4]', format(globalMethod(a$$b: 4)));
@@ skipping 23 matching lines @@
   Expect.equals('[1, 2, -, -]', format(t.psycho($:1, $$:2)));
   Expect.equals('[-, -, -, 4]', format(t.psycho($$$$: 4)));
 
   var obj = makeTestClass(0);
 
   Expect.equals('[1, 2, -, -]', format(obj.psycho($:1, $$:2)));
   Expect.equals('[-, -, -, 4]', format(obj.psycho($$$$: 4)));
   Expect.equals('[1, 2, 3, -]', format(obj.psycho($:1, $$:2, $$$:3)));
   Expect.equals('[1, 2, 3, -]', format(obj.psycho($$$:3, $$:2, $:1)));
 }