Move pub into sdk/lib/_internal.

sdk/lib/_internal/pub/test/install/hosted/fail_gracefully_on_url_resolve_test.dart

 // Copyright (c) 2012, 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 pub_tests;
 
 import 'dart:io';
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
@@ skipping 13 matching lines @@
           }
          }
       })
     ]).create();
 
     schedulePub(args: ['install'],
         error: new RegExp('Could not resolve URL "http://pub.invalid".'),
         exitCode: 1);
   });
 }