A good option 'dired-movement-style' was implemented in bug#65621.
But it supports only 'n' and 'p', but not counterpart '<' and '>'.
So I took the very nice algorithm that correctly handles the arg
on wrapping in 'dired-next-line', and refactored it to a separate
function 'dired--move-to-next-line' that is used in both:

dired-next-line:
  (dired--move-to-next-line arg #'dired--trivial-next-line)
dired-next-dirline:
  (dired--move-to-next-line arg #'dired--trivial-next-dirline)