nptl: Use <support/check.h> facilities in tst-setuid3

Remove local FAIL macro in favor to FAIL_EXIT1 from <support/check.h>,
which provides equivalent reporting, with the name of the file and the
line number within of the failure site additionally included.  Remove
FAIL_ERR altogether and include ": %m" explicitly with the format string
supplied to FAIL_EXIT1 as there seems little value to have a separate
macro just for this.

Reviewed-by: DJ Delorie <dj@redhat.com>
(cherry picked from commit 8c98195a)