Add close to input stream and cleanup socket and streams

runtime/bin/file.dart

Index: runtime/bin/file.dart
diff --git a/runtime/bin/file.dart b/runtime/bin/file.dart
index 9c0f509086c6a3fba34c978a4ff901e2d26b5ef5..3ad0ec7186899c101a08adc492e959edb1135415 100644
--- a/runtime/bin/file.dart
+++ b/runtime/bin/file.dart
@@ -80,14 +80,14 @@ interface File default _File {
    * input stream must be closed when no longer used to free up
    * system resources.
    */
-  FileInputStream openInputStream();
+  InputStream openInputStream();
 
   /**
    * Creates a new independent output stream for the file. The file
    * output stream must be closed when no longer used to free up
    * system resources.
    */
-  FileOutputStream openOutputStream();
+  OutputStream openOutputStream();
 
   /**
    * Get the name of the file.
@@ -254,15 +254,6 @@ interface RandomAccessFile {
 }
 
 
-interface FileInputStream extends InputStream {
-  void close();
-}
-
-
-interface FileOutputStream extends OutputStream {
-}
-
-
 class FileIOException implements Exception {
   const FileIOException([String this.message = ""]);
   String toString() => "FileIOException: $message";