Upgrade more confuse() functions

tests/compiler/dart2js_extra/23828_test.dart

 // Copyright (c) 2015, 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.
 
 // Regression test for http://dartbug.com/23828/
 // Used to fail when methods contain a name starting with `get`
 import 'package:expect/expect.dart';
 
-confuse(x) { return x; return x; }
+@NoInline()
+@AssumeDynamic()
+confuse(x) => x;
 
 class MA {
   noSuchMethod(i) => Expect.equals(i.positionalArguments.length, 1);
 }
 
 main() {
   confuse(new MA()).getFoo('a');
 }