Switch analyzer_cli to 'package:test'.

pkg/analyzer_cli/test/plugin_manager_test.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 analyzer_cli.test.plugin_manager_test;
 
 import 'package:analyzer/src/plugin/plugin_configuration.dart';
 import 'package:analyzer_cli/src/plugin/plugin_manager.dart';
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 
 main() {
   group('plugin manager tests', () {
     test('combine plugin info', () {
       PluginInfo localInfo = new PluginInfo(name: 'my_plugin');
       PluginInfo manifestInfo = new PluginInfo(
           className: 'MyPlugin', libraryUri: 'my_plugin/my_plugin.dart');
 
       PluginInfo merged = combine(localInfo, manifestInfo);
       expect(merged.name, equals('my_plugin'));
@@ skipping 64 matching lines @@
       expect(plugins[1].status, equals(PluginStatus.Applicable));
       expect(plugins[2].plugin.name, equals('my_plugin3'));
       expect(plugins[2].status, equals(PluginStatus.NotApplicable));
     });
   });
 }
 
 List<PluginDetails> sortByName(Iterable<PluginDetails> details) =>
     details.toList()
       ..sort((p1, p2) => p1.plugin.name.compareTo(p2.plugin.name));