Switch analyzer_cli to 'package:test'.

pkg/analyzer_cli/test/build_mode_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 analyzer_cli.test.built_mode;
 
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer_cli/src/build_mode.dart';
 import 'package:analyzer_cli/src/driver.dart';
 import 'package:analyzer_cli/src/options.dart';
 import 'package:bazel_worker/bazel_worker.dart';
 import 'package:bazel_worker/testing.dart';
 import 'package:protobuf/protobuf.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
-import 'package:unittest/unittest.dart';
 
 main() {
   defineReflectiveTests(WorkerLoopTest);
 }
 
 typedef void _TestWorkerLoopAnalyze(CommandLineOptions options);
 
 /**
  * [AnalyzerWorkerLoop] for testing.
  */
@@ skipping 107 matching lines @@
   List<int> _serializeProto(GeneratedMessage message) {
     var buffer = message.writeToBuffer();
 
     var writer = new CodedBufferWriter();
     writer.writeInt32NoTag(buffer.length);
     writer.writeRawBytes(buffer);
 
     return writer.toBuffer();
   }
 }