Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/services/correction/util_test.dart

 // Copyright (c) 2016, 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.correction.util;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/services/correction/strings.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/source.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
-import 'package:unittest/unittest.dart';
 
 import '../../abstract_single_unit.dart';
 import '../../utils.dart';
 
 main() {
   initializeTestEnvironment();
-  defineReflectiveTests(UtilTest);
+  defineReflectiveSuite(() {
+    defineReflectiveTests(UtilTest);
+  });
 }
 
 @reflectiveTest
 class UtilTest extends AbstractSingleUnitTest {
   test_addLibraryImports_dart_hasImports_between() {
     resolveTestUnit('''
 import 'dart:async';
 import 'dart:math';
 ''');
     LibraryElement newLibrary = _getDartLibrary('dart:collection');
@@ skipping 253 matching lines @@
   @override
   final String fullName;
 
   @override
   final Uri uri;
 
   _SourceMock(this.fullName, this.uri);
 
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 }