Update expectations for instance creations to match front_end.

pkg/front_end/testcases/inference/future_union_downwards_4.dart

Index: pkg/front_end/testcases/inference/future_union_downwards_4.dart
diff --git a/pkg/front_end/testcases/inference/future_union_downwards_4.dart b/pkg/front_end/testcases/inference/future_union_downwards_4.dart
index 197d68681b92491e42ba48c3b7a3c8fb97bfd6bf..3765bb73eacbffc3f61e20b255f970ed7928a7ca 100644
--- a/pkg/front_end/testcases/inference/future_union_downwards_4.dart
+++ b/pkg/front_end/testcases/inference/future_union_downwards_4.dart
@@ -17,7 +17,7 @@ class MyFuture<T> implements Future<T> {
 Future f;
 // Instantiates Future<int>
 Future<int> t1 = f.then(/*@returnType=MyFuture<int>*/ (/*@type=dynamic*/ _) =>
-    /*@typeArgs=int*/ new MyFuture.value('hi'));
+    new /*@typeArgs=int*/ MyFuture.value('hi'));
 
 // Instantiates List<int>
 Future<List<int>> t2 = f.then(
@@ -27,6 +27,6 @@ Future<List<int>> g2() async {
 }
 
 Future<List<int>> g3() async {
-  return /*@typeArgs=List<int>*/ new MyFuture.value(
+  return new /*@typeArgs=List<int>*/ MyFuture.value(
       /*@typeArgs=int*/ [3]);
 }