message: Print the thread name in Debug.
diff: @@ -131,7 +131,16 @@ impl<'mir, 'tcx> Thread<'mir, 'tcx> {
  impl<'mir, 'tcx> std::fmt::Debug for Thread<'mir, 'tcx> {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
  - write!(f, "{:?}", self.state)
  + if let Some(ref name) = self.thread_name {
  + if let Ok(name_str) = std::str::from_utf8(name) {
  + write!(f, "{}", name_str)?;
  + } else {
  + write!(f, "<invalid thread name>")?;
  + }
  + } else {
  + write!(f, "unnamed")?;
  + }
  + write!(f, "({:?}, {:?})", self.state, self.join_status)
  }
  }
  