Allow DirectoryDescriptor.load to load a file next to a directory.

pkg/scheduled_test/lib/src/descriptor/nothing_descriptor.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 descriptor.nothing;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:pathos/path.dart' as path;
@@ skipping 19 matching lines @@
     if (new File(fullPath).existsSync()) {
       throw "Expected nothing to exist at '$fullPath', but found a file.";
     } else if (new Directory(fullPath).existsSync()) {
       throw "Expected nothing to exist at '$fullPath', but found a "
           "directory.";
     } else {
       return;
     }
   });
 
-  Stream<List<int>> load(String pathToLoad) => errorStream("Nothing "
-      "descriptors don't support load().");
-
-  Stream<List<int>> read() => errorStream("Nothing descriptors don't support "
-      "read().");
-
   String describe() => "nothing at '$name'";
 }