Remove unused imports in pub.

sdk/lib/_internal/pub/test/install/relative_symlink_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 'package:scheduled_test/scheduled_test.dart';
-
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 
 main() {
   // Pub uses NTFS junction points to create links in the packages directory.
   // These (unlike the symlinks that are supported in Vista and later) do not
   // support relative paths. So this test, by design, will not pass on Windows.
   // So just skip it.
   if (Platform.operatingSystem == "windows") return;
 
@@ skipping 32 matching lines @@
       d.dir("bin", [
         d.dir("packages", [
           d.dir("myapp", [
             d.file('foo.dart', 'main() => "foo";')
           ])
         ])
       ])
     ]).validate();
   });
 }