Unify the server and plugin versions of the generators

pkg/analysis_server/test/domain_diagnostic_test.dart

 // Copyright (c) 2015, 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.domain.diagnostic;
-
-import 'package:analysis_server/plugin/protocol/protocol.dart';
+import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/domain_diagnostic.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'analysis_abstract.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(DiagnosticDomainTest);
     defineReflectiveTests(DiagnosticDomainTest_Driver);
@@ skipping 43 matching lines @@
 
 @reflectiveTest
 class DiagnosticDomainTest_Driver extends DiagnosticDomainTest {
   @override
   void setUp() {
     enableNewAnalysisDriver = true;
     generateSummaryFiles = true;
     super.setUp();
   }
 }