bug#47207: 28.0.50; decode_next_window_args crash

[Gregory Heytings]

> Having just managed to "solve this issue" here in a more or less elegant 
> way, Alan beat me to it with a new twist.  To reproduce with emacs -Q do
>
> (custom-set-variables
> '(tooltip-reuse-hidden-frame t)
> '(x-gtk-use-system-tooltips nil))
>
> show a tooltip (by moving the mouse over the mode line for example) and 
> then type C-h f followed by C-g.

This is because of commit 7c2ebf6e23.