Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/services/dependencies/test_all.dart

 // Copyright (c) 2015, 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.services.dependencies;
 
-import 'package:unittest/unittest.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../utils.dart';
 import 'library_dependencies_test.dart' as library_dependencies;
 import 'reachable_source_collector_test.dart' as reachable_source_collector;
 
 /// Utility for manually running all tests.
 main() {
   initializeTestEnvironment();
-  group('dependencies', () {
+  defineReflectiveSuite(() {
     library_dependencies.main();
     reachable_source_collector.main();
-  });
+  }, name: 'dependencies');
 }