bug#54028: Window is not a valid window

[martin rudalics]

Eli, is the below OK to install on the release branch?  It's a trivial
safety check that would fix this bug.

Thanks, martin


--- a/lisp/window.el
+++ b/lisp/window.el
@@ -6394,7 +6394,8 @@ window-state-put
        (window--state-put-2 ignore pixelwise))
       (while window-state-put-stale-windows
        (let ((window (pop window-state-put-stale-windows)))
-         (when (eq (window-deletable-p window) t)
+         (when (and (window-valid-p window)
+                     (eq (window-deletable-p window) t))
            (delete-window window))))
       (window--check frame))))