Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/analysis/notification_navigation_test.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.analysis.notification.navigation;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/constants.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
-import 'package:unittest/unittest.dart';
 
 import '../analysis_abstract.dart';
 import '../utils.dart';
 
 main() {
   initializeTestEnvironment();
-  defineReflectiveTests(AnalysisNotificationNavigationTest);
+  defineReflectiveSuite(() {
+    defineReflectiveTests(AnalysisNotificationNavigationTest);
+  });
 }
 
 class AbstractNavigationTest extends AbstractAnalysisTest {
   List<NavigationRegion> regions;
   List<NavigationTarget> targets;
   List<String> targetFiles;
 
   NavigationRegion testRegion;
   List<int> testTargetIndexes;
   List<NavigationTarget> testTargets;
@@ skipping 897 matching lines @@
 
   test_type_void() async {
     addTestFile('''
 void main() {
 }
 ''');
     await prepareNavigation();
     assertNoRegionAt('void');
   }
 }