Move pub into sdk/lib/_internal.

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

 // 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))));
 }