ZTS: Add a test to verify that copy_file_range obeys RLIMIT_FSIZE

Signed-off-by: Mark Johnston <markj@FreeBSD.org>

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>