bug#45915: 28.2; delete-char deletes two letters

[Tak Kunihiro <homeros.misasa@gmail.com>]

OK. Now I understand <delete> only deletes one letter.  Two spaces are
shown as one letter, as expected.

To have a distorted table soon after deletion of text is OK.

However, when two spaces are shown as one letter, point moves randomly
when I press <up>.  I cannot keep editing with this condition.

I show recipe to reproduce this situation. Is there a trick to move
point in expected way?

(defun emacs-bug-reproduce-45915 ()
  "Reproduce bug#45915."
  ;; (gnus-read-ephemeral-emacs-bug-group 45915)
  (interactive)
  (with-current-buffer (get-buffer-create "*temp buffer*")
    (erase-buffer)
    (require 'org)
    (orgtbl-mode 1)
    (insert (format "emacs-version: %s, org-version: %s\n" emacs-version org-version))
    (insert "| 1 |   |   |   |   |   |   |   |   |"))
  (switch-to-buffer-other-window "*temp buffer*")
  (execute-kbd-macro (kbd "M-< C-n C-f C-f"))
  (message "I will call #'org-table-copy-down.")
  (sit-for 2)
  (call-interactively #'org-table-copy-down)
  (sit-for 2)
  (message "I will hit <delete>.")
  (sit-for 2)
  (execute-kbd-macro (kbd "<delete>"))
  (message "One letter was deleted expectedly.")
  (sit-for 2)
  (message "I will hit <up>.")
  (sit-for 2)
  (execute-kbd-macro (kbd "<up>"))
  (message "Point moved unexpectedly."))
;;; (call-interactively 'emacs-bug-reproduce-45915)