Generate constants in server as we do in plugin

pkg/analysis_server/test/integration/support/integration_test_methods.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.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
 /**
  * Convenience methods for running integration tests
@@ skipping 1543 matching lines @@
         decoder, 'result', result);
   }
 
   /**
    * Return a list of all postfix templates currently available.
    *
    * Returns
    *
    * templates: List<PostfixTemplateDescriptor>
    *
-   *   The list of available template.
+   *   The list of available templates.
    */
   Future<EditListPostfixCompletionTemplatesResult>
       sendEditListPostfixCompletionTemplates() async {
     var result = await server.send("edit.listPostfixCompletionTemplates", null);
     ResponseDecoder decoder = new ResponseDecoder(null);
     return new EditListPostfixCompletionTemplatesResult.fromJson(
         decoder, 'result', result);
   }
 
   /**
@@ skipping 500 matching lines @@
         outOfTestExpect(params, isExecutionLaunchDataParams);
         _onExecutionLaunchData.add(
             new ExecutionLaunchDataParams.fromJson(decoder, 'params', params));
         break;
       default:
         fail('Unexpected notification: $event');
         break;
     }
   }
 }