Generate constants in server as we do in plugin

pkg/analysis_server/test/analysis/notification_analysis_options_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.
 
 import 'package:analysis_server/protocol/protocol.dart';
+import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart'
     hide AnalysisOptions;
-import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:linter/src/rules.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../analysis_abstract.dart';
 import '../mocks.dart';
 
@@ skipping 26 matching lines @@
   void addOptionsFile(String contents) {
     addFile(optionsFilePath, contents);
   }
 
   void deleteFile(String filePath) {
     resourceProvider.deleteFile(filePath);
   }
 
   @override
   void processNotification(Notification notification) {
-    if (notification.event == ANALYSIS_ERRORS) {
+    if (notification.event == ANALYSIS_NOTIFICATION_ERRORS) {
       var decoded = new AnalysisErrorsParams.fromNotification(notification);
       filesErrors[decoded.file] = decoded.errors;
     }
   }
 
   void setAnalysisRoot() {
     Request request =
         new AnalysisSetAnalysisRootsParams([projectPath], []).toRequest('0');
     handleSuccessfulRequest(request);
   }
@@ skipping 259 matching lines @@
   @override
   String get optionsFilePath => '$projectPath/analysis_options.yaml';
 }
 
 @reflectiveTest
 class OldAnalysisOptionsFileNotificationTest
     extends AnalysisOptionsFileNotificationTest {
   @override
   String get optionsFilePath => '$projectPath/.analysis_options';
 }