Fixes #28338

tests/language_strong/await_in_cascade_test.dart

Index: tests/language_strong/await_in_cascade_test.dart
diff --git a/tests/language_strong/await_in_cascade_test.dart b/tests/language_strong/await_in_cascade_test.dart
index e9fbcf9bda79decf92d7461c7cedfa2781c6e976..dc1f30226c75ef370467bc1d25c08909a119fe4a 100644
--- a/tests/language_strong/await_in_cascade_test.dart
+++ b/tests/language_strong/await_in_cascade_test.dart
@@ -4,6 +4,7 @@
 
 import 'dart:async';
 import 'package:expect/expect.dart';
+import "package:async_helper/async_helper.dart";
 
 class C {
   Future<List<int>> m() async => []..add(await _m());
@@ -11,5 +12,7 @@ class C {
 }
 
 main() async {
-  Expect.equals(await new C().m(), 42);
+  asyncStart();
+  Expect.equals((await new C().m()).first, 42);
+  asyncEnd();
 }