bug#2136: cleanup: Fresume_tty and Fsuspend_tty

[Eli Zaretskii]

> Date: Sat, 31 Jan 2009 10:46:45 -0800 (PST)
> From: Dan Nicolaescu <dann@ics.uci.edu>
> Cc: 
> 
> These functions should not have any #ifdef MSDOS  or #ifdef subprocesses,
> they cannot be used on such systems.

The only uses up till now don't have any trouble.

> That code is clearly untested anyway.

I did test them at the time.