Move ChangeBuilder to analyzer_plugin

pkg/analyzer_plugin/test/src/utilities/test_all.dart

 // Copyright (c) 2017, 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.
 
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
-import 'channel/test_all.dart' as channel;
+import 'change_builder/test_all.dart' as change_builder;
 
 main() {
   defineReflectiveSuite(() {
-    channel.main();
-  }, name: 'src');
+    change_builder.main();
+  }, name: 'utilities');
 }