pkg/analysis_server: fixes for unittest deprecations

pkg/analysis_server/test/protocol_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.protocol;
 
+import 'dart:convert';
+
 import 'package:analysis_server/src/protocol.dart';
-import 'package:unittest/matcher.dart';
 import 'package:unittest/unittest.dart';
-import 'dart:convert';
 
 main() {
   group('Notification', () {
     test('getParameter_defined', NotificationTest.getParameter_defined);
     test('getParameter_undefined', NotificationTest.getParameter_undefined);
     test('fromJson', NotificationTest.fromJson);
     test('fromJson_withParams', NotificationTest.fromJson_withParams);
   });
   group('Request', () {
     test('getParameter_defined', RequestTest.getParameter_defined);
@@ skipping 219 matching lines @@
   static void fromJson_withResult() {
     Response original = new Response('myId');
     original.setResult('foo', 'bar');
     Response response = new Response.fromJson(original.toJson());
     expect(response.id, equals('myId'));
     Map<String, Object> result = response.result;
     expect(result.length, equals(1));
     expect(result['foo'], equals('bar'));
   }
 }