Upgrade some tests to use annotations instead of 'clever' confuse() function

tests/compiler/dart2js_extra/useful_error_message_1_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.
 
 // Test that closures have a useful string that identifies the function by name
 // in error messages.
 
 import "package:expect/expect.dart";
 
-@NoInline
-@AssumeDynamic
+@NoInline()
+@AssumeDynamic()
 confuse(x) => x;
 
 class CCCC {
   instanceMethod([a, b]) => '[$a, $b]';
   static staticMethod() => 'hi';
   // Default `toString` method returns "Instance of 'CCCC'" or similar with a
   // shorter name if minified.
 }
 
 main() {
@@ skipping 52 matching lines @@
   checkContains(s5, "main_closure");
   checkContains('$anon', "main_closure");
 
   // Local named closure.
   localFunction() => c;
   var e6 = new ArgumentError.value(localFunction);
   var s6 = '$e6';
   checkContains(s6, "localFunction");
   checkContains('$localFunction', "localFunction");
 }