Update expectations for instance creations to match front_end.

pkg/front_end/testcases/inference/downwards_inference_async_await.dart

 // Copyright (c) 2017, 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.
 
 /*@testedFeatures=inference*/
 library test;
 
 import 'dart:async';
 
 Future test() async {
   dynamic d;
   List<int> l0 =
       await /*@typeArgs=int*/ [/*info:DYNAMIC_CAST*/ /*@promotedType=none*/ d];
-  List<int> l1 = await /*@typeArgs=List<int>*/ new Future.value(
+  List<int> l1 = await new /*@typeArgs=List<int>*/ Future.value(
       /*@typeArgs=dynamic*/ [/*@promotedType=none*/ d]);
 }