Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/services/refactoring/rename_label_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.services.refactoring.rename_label;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
-import 'package:unittest/unittest.dart';
 
 import '../../utils.dart';
 import 'abstract_rename.dart';
 
 main() {
   initializeTestEnvironment();
-  defineReflectiveTests(RenameLabelTest);
+  defineReflectiveSuite(() {
+    defineReflectiveTests(RenameLabelTest);
+  });
 }
 
 @reflectiveTest
 class RenameLabelTest extends RenameRefactoringTest {
   test_checkNewName_LocalVariableElement() {
     indexTestUnit('''
 main() {
 test:
   while (true) {
     break test;
@@ skipping 49 matching lines @@
     break test;
   }
 }
 ''');
     // configure refactoring
     createRenameRefactoringAtString('test:');
     // old name
     expect(refactoring.oldName, 'test');
   }
 }