Remove more libraries directives from server

pkg/analysis_server/lib/src/services/search/hierarchy.dart

 // Copyright (c) 2014, 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 services.hierarchy;
-
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/services/search/element_visitors.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 
 /**
  * Returns direct children of [parent].
@@ skipping 138 matching lines @@
  * its variable, otherwise returns [element].
  */
 Element getSyntheticAccessorVariable(Element element) {
   if (element is PropertyAccessorElement) {
     if (element.isSynthetic) {
       return element.variable;
     }
   }
   return element;
 }