Update confuse() on syncstar_less_than_test

tests/language/syncstar_less_than_test.dart

 // Copyright (c) 2015, the Dart Team. All rights reserved. Use of this
 // source code is governed by a BSD-style license that can be found in
 // the LICENSE file.
 
 import "package:expect/expect.dart";
 
-confuse(x) => [1, 'x', true, null, x].last;
+@NoInline() @AssumeDynamic()
+confuse(x) => x;
 
 Iterable<int> foo() sync* {
  var a = confuse(1);
  if (a < 10) {
    yield 2;
  }
 }
 
 main() {
   Expect.listEquals(foo().toList(), [2]);
-}
+}