Move pub into sdk/lib/_internal.

sdk/lib/_internal/pub/test/install/hosted/repair_cache_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 'package:pathos/path.dart' as path;
 
-import '../../../../pub/io.dart';
+import '../../../lib/src/io.dart';
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   initConfig();
   integration('re-installs a package if it has an empty "lib" directory', () {
     servePackages([packageMap("foo", "1.2.3")]);
 
     // Set up a cache with a broken foo package.
     d.dir(cachePath, [
@@ skipping 34 matching lines @@
 
     d.appDir([dependencyMap("foo", "1.2.3")]).create();
 
     schedulePub(args: ['install'],
         output: new RegExp("Dependencies installed!\$"));
 
     d.cacheDir({"foo": "1.2.3"}).validate();
     d.packagesDir({"foo": "1.2.3"}).validate();
   });
 }