Reapply revert of "Make stdout/stderr async"

tests/standalone/io/stdout_stderr_non_blocking_test.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:convert";
 import "dart:io";
 
 callIOSink(IOSink sink) {
   // Call all methods on IOSink.
@@ skipping 14 matching lines @@
   future.then((_) {
     controller = new StreamController(sync: true);
     controller.stream.pipe(sink);
     controller.add([72, 101, 108]);
     controller.add([108, 111, 10]);
     controller.close();
   });
 }
 
 main() {
-  callIOSink(stdout);
-  stdout.done.then((_) {
-    callIOSink(stderr);
-    stderr.done.then((_) {
+  callIOSink(stdout.nonBlocking);
+  stdout.nonBlocking.done.then((_) {
+    callIOSink(stderr.nonBlocking);
+    stderr.nonBlocking.done.then((_) {
       stdout.close();
       stderr.close();
     });
   });
 }