* mandos-ctl: Update Emacs lisp after-save-hook test runner to use file-local-name if available (i.e. Emacs 26), or to use file-remote-p if not (Emacs 25). Either should be more general than the tramp-* functions were. Also use process-file-shell-command instead of shell-command, which enables the use of the less intrusive display-buffer-in-side-window action function argument to display-buffer. This stops the takeover of buffers (and/or disappearance of windows) when saving.