Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/validator/utils.dart

Index: sdk/lib/_internal/pub_generated/test/validator/utils.dart
diff --git a/sdk/lib/_internal/pub_generated/test/validator/utils.dart b/sdk/lib/_internal/pub_generated/test/validator/utils.dart
deleted file mode 100644
index def5bb9878d61a6610176d2ce59315043f02cf5b..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/test/validator/utils.dart
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright (c) 2013, 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.
-
-library validator.utils;
-
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../test_pub.dart';
-
-void expectNoValidationError(ValidatorCreator fn) {
-  expect(schedulePackageValidation(fn), completion(pairOf(isEmpty, isEmpty)));
-}
-
-void expectValidationError(ValidatorCreator fn) {
-  expect(
-      schedulePackageValidation(fn),
-      completion(pairOf(isNot(isEmpty), anything)));
-}
-
-void expectValidationWarning(ValidatorCreator fn) {
-  expect(
-      schedulePackageValidation(fn),
-      completion(pairOf(isEmpty, isNot(isEmpty))));
-}