Replace @ReflectiveTestCase() with @reflectiveTest.

pkg/analysis_server/test/services/correction/assist_test.dart

 // Copyright (c) 2014, 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.services.correction.assist;
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/local_memory_index.dart';
 import 'package:analysis_server/src/services/search/search_engine_internal.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../abstract_single_unit.dart';
 import '../../reflective_tests.dart';
 
 
 main() {
   groupSep = ' | ';
   runReflectiveTests(AssistProcessorTest);
 }
 
 
-@ReflectiveTestCase()
+@reflectiveTest
 class AssistProcessorTest extends AbstractSingleUnitTest {
   Index index;
   SearchEngineImpl searchEngine;
 
   int offset;
   int length;
 
   Assist assist;
   SourceChange change;
   String resultCode;
@@ skipping 2591 matching lines @@
   void _indexTestUnit(String code) {
     resolveTestUnit(code);
     index.indexUnit(context, testUnit);
   }
 
   void _setStartEndSelection() {
     offset = findOffset('// start\n') + '// start\n'.length;
     length = findOffset('// end') - offset;
   }
 }