Update Dart binaries to 1.18.0-dev.4.4

tests/dartino_tests/snapshot_stacktrace_tests.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' show
     Future,
     Stream,
     StreamController;
 
 import 'dart:io' show
@@ skipping 34 matching lines @@
 
 Future<Map<String, NoArgFuture>> listTests(
     [bool writeGoldenFiles = false]) async {
   Map<String, NoArgFuture> tests = new Map<String, NoArgFuture>();
 
   Directory directory =
     new Directory(testDirectory());
 
   String suffix = "_test.dart";
 
-  Iterable<File> testFiles = directory.listSync().where((FileSystemEntity e) {
+  Iterable<FileSystemEntity> testFiles = directory.listSync().where((FileSystemEntity e) {
     return e is File && e.path.endsWith(suffix);
   });
 
   testFiles.forEach((File file) {
     String path = file.path;
     String filename = path.split(Platform.pathSeparator).last;
     String name = filename.substring(0, filename.length - suffix.length);
     tests["snapshot_stacktrace_tests/$name"] =
         () => runTest(name, writeGoldenFiles);
   });
@@ skipping 60 matching lines @@
 
 String testDirectory([String generated = ''])
     => 'tests/snapshot_stacktrace_tests$generated';
 
 main() async {
   var tests = await listTests(true);
   for (var name in tests.keys) {
     await tests[name]();
   }
 }