[LTP] [PATCH v2] Refactor timer_getoverrun test using new LTP API

[Cyril Hrubis]

Hi!
> Test looks fine apart from the issues I have with any test which fails
> if a different error number is returned. I already started that
> discussion here:
> 
> https://patchwork.ozlabs.org/project/ltp/patch/20230901144433.2526-1-chrubis@suse.cz/#3191079

Since we have decided to solve this problem inside of the TST_EXP_FAIL()
macro this shouldn't block this patch.

-- 
Cyril Hrubis
chrubis@suse.cz