gh-110392: Fix tty functions (GH-110642)

* tty.setraw() and tty.setcbreak() previously returned partially modified
  list of the original tty attributes. Now they return the correct list of
  the original tty attributes

* tty.cfmakeraw() and tty.cfmakecbreak() now make a copy of the list of
  special characters before modifying it.
3 files changed