message: Remove fd_entry lookup on stdin,out,err for wasi::poll_oneoff
diff: @@ -2267,18 +2267,29 @@ pub fn poll_oneoff(
  let fd = match s.event_type {
  EventType::Read(__wasi_subscription_fs_readwrite_t { fd }) => {
  + match fd {
  + __WASI_STDIN_FILENO | __WASI_STDOUT_FILENO | __WASI_STDERR_FILENO => (),
  + _ => {
  let fd_entry = wasi_try!(state.fs.get_fd(fd));
  if !has_rights(fd_entry.rights, __WASI_RIGHT_FD_READ) {
  return __WASI_EACCES;
  }
  + }
  + }
  in_events.push(peb.add(PollEvent::PollIn).build());
  Some(fd)
  }
  EventType::Write(__wasi_subscription_fs_readwrite_t { fd }) => {
  + match fd {
  + __WASI_STDIN_FILENO | __WASI_STDOUT_FILENO | __WASI_STDERR_FILENO => (),
  + _ => {
  let fd_entry = wasi_try!(state.fs.get_fd(fd));
  +
  if !has_rights(fd_entry.rights, __WASI_RIGHT_FD_WRITE) {
  return __WASI_EACCES;
  }
  + }
  + }
  in_events.push(peb.add(PollEvent::PollOut).build());
  Some(fd)
  }
  