Update the streams interfaces

runtime/bin/file.dart

Index: runtime/bin/file.dart
diff --git a/runtime/bin/file.dart b/runtime/bin/file.dart
index 58db9eacc0672e7ca04844b564594ea590371f9d..ebffd2c6008bf1966b9f3a007468e71dc107fa58 100644
--- a/runtime/bin/file.dart
+++ b/runtime/bin/file.dart
@@ -2,14 +2,6 @@
 // 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.
 
-interface FileInputStream extends InputStream factory _FileInputStream {
-  FileInputStream(File file);
-}
-
-interface FileOutputStream extends OutputStream factory _FileOutputStream {
-  FileOutputStream(File file);
-}
-
 interface File factory _File {
   // Open a file.
   File(String name, bool writable);