tests: allow any error code when trying to set time

tests: allow any error code when trying to set time

Lower expectations of particular error code numbers when trying to set
time.  This helps to workaround issues with unexpected return codes
in some exotic environments where EPERM is returned instead of EINVAL
(e.g. mock that uses systemd-nspawn).

* tests/clock_xettime.c (main): Do not hardcode EINVAL, print return
codes using sprintrc.
* tests/xettimeofday.c (main): Likewise.
* NEWS: Mention this fix.

Co-Authored-by: Dmitry V. Levin <ldv@altlinux.org>