Unify the server and plugin versions of the generators

pkg/analysis_server/test/analysis/set_priority_files_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.analysis.set_priority_files;
 
-import 'package:analysis_server/plugin/protocol/protocol.dart';
+import 'package:analysis_server/protocol/protocol.dart';
+import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:analyzer/src/generated/engine.dart'
     show InternalAnalysisContext;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../analysis_abstract.dart';
 import '../mocks.dart';
@@ skipping 122 matching lines @@
     expect(params, isNotNull);
     expect(params.files, <String>[testFile]);
   }
 
   _setPriorityFile(String file) async {
     Request request =
         new AnalysisSetPriorityFilesParams(<String>[file]).toRequest('0');
     return await serverChannel.sendRequest(request);
   }
 }