bug#29957: 27.0.50; xgettype (and friends) don't know about Lisp_Word

[Stefan Monnier]

Package: Emacs
Version: 27.0.50


    % cd .../emacs/src
    % gdb emacs
    (gdb) b main
    (gdb) r
    (gdb) xgettype Qnil

Tells me "Argument to arithmetic operation not a number or boolean."
`xbacktrace` says the same.

This seems to be due to the recent change to the representation of
List_Object.


        Stefan