Small fixes to top level type inference.

pkg/front_end/testcases/inference/downwards_inference_inside_top_level_2.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;
 
 class A<T> {
   A(T x);
 }
 
 var /*@topType=List<A<int>>*/ t1 = <A<int>>[new /*@typeArgs=int*/ A(1)];
-var /*@topType=List<A<dynamic>>*/ t2 = /*@typeArgs=A<dynamic>*/ [
-  new
-      /*error:TOP_LEVEL_TYPE_ARGUMENTS*/ /*@typeArgs=dynamic*/ A(2)
-];
 
 main() {}