Make analyzer strong-mode clean

pkg/analyzer/test/src/context/builder_test.dart

 // Copyright (c) 2016, 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.context.context_builder_test;
 
 import 'dart:io' as io;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
@@ skipping 661 matching lines @@
     expect(actual.analyzeFunctionBodiesPredicate,
         same(expected.analyzeFunctionBodiesPredicate));
     expect(actual.cacheSize, expected.cacheSize);
     expect(actual.dart2jsHint, expected.dart2jsHint);
     expect(actual.enableAssertMessage, expected.enableAssertMessage);
     expect(actual.enableAsync, expected.enableAsync);
     expect(actual.enableStrictCallChecks, expected.enableStrictCallChecks);
     expect(actual.enableGenericMethods, expected.enableGenericMethods);
     expect(actual.enableSuperMixins, expected.enableSuperMixins);
     expect(actual.enableTiming, expected.enableTiming);
-    expect(actual.enableTrailingCommas, expected.enableTrailingCommas);
     expect(actual.generateImplicitErrors, expected.generateImplicitErrors);
     expect(actual.generateSdkErrors, expected.generateSdkErrors);
     expect(actual.hint, expected.hint);
     expect(actual.incremental, expected.incremental);
     expect(actual.incrementalApi, expected.incrementalApi);
     expect(actual.incrementalValidation, expected.incrementalValidation);
     expect(actual.lint, expected.lint);
     expect(actual.preserveComments, expected.preserveComments);
     expect(actual.strongMode, expected.strongMode);
     expect(actual.strongModeHints, expected.strongModeHints);
     expect(actual.implicitCasts, expected.implicitCasts);
     expect(actual.implicitDynamic, expected.implicitDynamic);
     expect(actual.trackCacheDependencies, expected.trackCacheDependencies);
     expect(actual.finerGrainedInvalidation, expected.finerGrainedInvalidation);
   }
 }