Integration test search.getTypeHierarchy and make some minor fixes.

pkg/analysis_server/test/integration/protocol_matchers.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.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/spec/generate_files".
 
 /**
  * Matchers for data types defined in the analysis server API
@@ skipping 498 matching lines @@
 final Matcher isSearchGetTypeHierarchyParams = new MatchesJsonObject(
   "search.getTypeHierarchy params", {
     "file": isFilePath,
     "offset": isInt
   });
 
 /**
  * search.getTypeHierarchy result
  *
  * {
- *   "hierarchyItems": List<TypeHierarchyItem>
+ *   "hierarchyItems": optional List<TypeHierarchyItem>
  * }
  */
 final Matcher isSearchGetTypeHierarchyResult = new MatchesJsonObject(
-  "search.getTypeHierarchy result", {
+  "search.getTypeHierarchy result", null, optionalFields: {
     "hierarchyItems": isListOf(isTypeHierarchyItem)
   });
 
 /**
  * search.results params
  *
  * {
  *   "id": SearchId
  *   "results": List<SearchResult>
  *   "last": bool
@@ skipping 1332 matching lines @@
  *
  * {
  *   "newName": String
  * }
  */
 final Matcher isRenameOptions = new MatchesJsonObject(
   "rename options", {
     "newName": isString
   });