Fix a number of issues with the process handling

runtime/bin/builtin.dart

 // Copyright (c) 2011, 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.
 
 #library("builtin");
 #import("dart:nativewrappers");
 #import("dart:coreimpl");
 
 void print(arg) {
   _Logger._printString(arg.toString());
 }
 
 void exit(int status) {
   if (status is !int) {
     throw new IllegalArgumentException("int status expected");
   }
   _exit(status);
 }
 
 Socket _stdin;
-OutputStream get stdin() {
+InputStream get stdin() {
   if (_stdin == null) {
     _stdin = new _Socket._internalReadOnly();
     _getStdioHandle(_stdin, 0);
   }
   return _stdin.inputStream;
 }
 
 Socket _stdout;
 OutputStream get stdout() {
   if (_stdout == null) {
@@ skipping 12 matching lines @@
   return _stderr.outputStream;
 }
 
 _exit(int status) native "Exit";
 
 _getStdioHandle(Socket socket, int num) native "Socket_GetStdioHandle";
 
 class _Logger {
   static void _printString(String s) native "Logger_PrintString";
 }