Upgrade more confuse() functions

tests/compiler/dart2js_extra/mirrors_used_closure_test.dart

 // Copyright (c) 2014, 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.
 
 library MirrorsTest;
 
 import 'package:expect/expect.dart';
 
 @MirrorsUsed(targets: const ['A.foo', 'B.bar'])
 import 'dart:mirrors';
 
 class A {
   foo() => 42;
   bar() => 499;
 }
 
 class B {
   bar() => 33;
 }
 
-// Uses DateTime.now to make it impossible to predict.
-// Uses recursive call to make it harder to inline.
-confuse(x) {
-  if (new DateTime.now().millisecondsSinceEpoch == 42) return confuse(x + 1);
-  return x;
-}
+@NoInline()
+@AssumeDynamic()
+confuse(x) => x;
 
 main() {
   var f = [new A(), new B()][confuse(0)].bar;
   Expect.throws(() => reflect(f).invoke(#call, [], {}),
                 (e) => e is UnsupportedError);
 }