Infinite down arrow key input at auto-pause prompt just before form-feed

When displaying a file (e.g. with JS console.printfile()) that contains a form-feed (Ctrl-L) character, the auto-pause prompt that will appear doesn't handle down-arrow very well and just loops forever until a non-down-arrow key is pressed (or the user disconnects).

Looking at the git blame, it appears this problem has been there as long as the pause prompt has accepted down-arrow (Ctrl-J) as a special input character (to display just one more line) - so, a very long time.