bug#65217: 29.1; set-frame-size gets confused and drops calls

[Gregory Heytings]

Ash, can you please try the following variant of your recipe?  Does it do 
what you want?

(setq my/frame
      (make-frame `((left . 500)
                    (top . 5)
                    (width . 20)
                    (height . 20)
                    (parent-frame . ,(selected-frame)))))

(defun my/twiddle (width height)
  (set-frame-size my/frame 10 10)
  (redisplay t)
  (set-frame-size my/frame width height)
  (redisplay t)
  (message (format "%s %s" (frame-width my/frame) (frame-height my/frame))))