Unify the server and plugin versions of the generators

pkg/analysis_server/test/src/plugin/result_merger_test.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:analysis_server/plugin/protocol/protocol.dart';
+import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/plugin/result_merger.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';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(ResultMergerTest);
   });
 }
@@ skipping 714 matching lines @@
   }
 
   void test_overlaps_true_onLeft() {
     expect(merger.overlaps(1, 5, 3, 7), isTrue);
   }
 
   void test_overlaps_true_onRight() {
     expect(merger.overlaps(3, 7, 1, 5), isTrue);
   }
 }