* 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.
(cherry picked from commit 84e2096fbd)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>