Break up another large file

pkg/analyzer/test/src/task/options_work_manager_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 analyzer.test.src.task.options_work_manager_test;
 
+import 'package:analyzer/error/error.dart' show AnalysisError;
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/src/context/cache.dart';
+import 'package:analyzer/src/error/codes.dart' show AnalysisOptionsErrorCode;
 import 'package:analyzer/src/generated/engine.dart'
     show
         AnalysisEngine,
         AnalysisErrorInfo,
         AnalysisErrorInfoImpl,
         CacheState,
         ChangeNoticeImpl,
         InternalAnalysisContext;
-import 'package:analyzer/src/generated/error.dart'
-    show AnalysisError, AnalysisOptionsErrorCode;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/task/options.dart';
 import 'package:analyzer/src/task/options_work_manager.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:analyzer/task/general.dart';
 import 'package:analyzer/task/model.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:typed_mock/typed_mock.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 261 matching lines @@
       errors = getCacheEntry(source).getValue(ANALYSIS_OPTIONS_ERRORS);
     }
     return new AnalysisErrorInfoImpl(
         errors, getCacheEntry(source).getValue(LINE_INFO));
   }
 
   @override
   ChangeNoticeImpl getNotice(Source source) =>
       _pendingNotices.putIfAbsent(source, () => new ChangeNoticeImpl(source));
 }