Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/integration/search/test_all.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 test.integration.search.all;
 
-import 'package:unittest/unittest.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../utils.dart';
 import 'get_type_hierarchy_test.dart' as get_type_hierarchy_test;
 
 /**
  * Utility for manually running all integration tests.
  */
 main() {
   initializeTestEnvironment();
-  group('search', () {
+  defineReflectiveSuite(() {
     get_type_hierarchy_test.main();
-  });
+  }, name: 'search');
 }