fix include options test on windows

pkg/analyzer/test/source/analysis_options_provider_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.source.analysis_options_provider_test;
 
 import 'dart:core';
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
@@ skipping 175 matching lines @@
   }
 
   void test_getOptions_empty() {
     pathTranslator.newFile('/$optionsFileName', r'''#empty''');
     Map<String, YamlNode> options = _getOptions('/');
     expect(options, isNotNull);
     expect(options, isEmpty);
   }
 
   void test_getOptions_include() {
-    if (isWindows) {
-      // TODO(danrubel) fix on Windows.
-      return;
-    }
     pathTranslator.newFile(
         '/foo.include',
         r'''
 analyzer:
   ignore:
     - ignoreme.dart
     - 'sdk_ext/**'
 ''');
     pathTranslator.newFile(
         '/$optionsFileName',
         r'''
-include: /foo.include
+include: foo.include
 ''');
     Map<String, YamlNode> options = _getOptions('/');
     expect(options, hasLength(1));
     {
       YamlMap analyzer = options['analyzer'];
       expect(analyzer, hasLength(1));
       {
         YamlList ignore = analyzer['ignore'];
         expect(ignore, hasLength(2));
         expect(ignore[0], 'ignoreme.dart');
@@ skipping 40 matching lines @@
         expect(ignore[1], 'sdk_ext/**');
       }
     }
   }
 
   Map<String, YamlNode> _getOptions(String posixPath, {bool crawlUp: false}) {
     Resource resource = pathTranslator.getResource(posixPath);
     return provider.getOptions(resource, crawlUp: crawlUp);
   }
 }