dart:io | Add additional test of directory listing of broken links.

tests/standalone/io/link_test.dart

Index: tests/standalone/io/link_test.dart
diff --git a/tests/standalone/io/link_test.dart b/tests/standalone/io/link_test.dart
index bf76f68d9028ac84fd24dbfac8a3ab70062ff469..0562cb3bb61e93d42cf5f75c44f948e310d7cb27 100644
--- a/tests/standalone/io/link_test.dart
+++ b/tests/standalone/io/link_test.dart
@@ -133,6 +133,15 @@ testCreateSync() {
     }
   }
   Future.wait(futures).then((_) {
+    new Directory(target).deleteSync(recursive: true);
+    for (bool recursive in [true, false]) {
+      for (bool followLinks in [true, false]) {
+        var result = baseDir.listSync(recursive: recursive,
+                                      followLinks: followLinks);
+        Expect.equals(1, result.length);
+        Expect.isTrue(result[0] is Link);
+      }
+    }
     baseDir.deleteSync(recursive: true);
   });
 }