Remove uses of the old plugin model from the analysis server

pkg/analysis_server/test/edit/format_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 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
-import 'package:plugin/manager.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../analysis_abstract.dart';
 import '../mocks.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(FormatTest);
   });
 }
 
 @reflectiveTest
 class FormatTest extends AbstractAnalysisTest {
   @override
   void setUp() {
     super.setUp();
     createProject();
-    ExtensionManager manager = new ExtensionManager();
-    manager.processPlugins([server.serverPlugin]);
     handler = new EditDomainHandler(server);
   }
 
   Future test_format_longLine() {
     String content = '''
 fun(firstParam, secondParam, thirdParam, fourthParam) {
   if (firstParam.noNull && secondParam.noNull && thirdParam.noNull && fourthParam.noNull) {}
 }
 ''';
     addTestFile(content);
@@ skipping 77 matching lines @@
   EditFormatResult _formatAt(int selectionOffset, int selectionLength,
       {int lineLength}) {
     Request request = new EditFormatParams(
             testFile, selectionOffset, selectionLength,
             lineLength: lineLength)
         .toRequest('0');
     Response response = handleSuccessfulRequest(request);
     return new EditFormatResult.fromResponse(response);
   }
 }