Use clock_gettime() instead of gettimeofday() for isc_stdtime function
requested to merge 1679-remove-workaround-for-systems-with-broken-gettimeofday-system-calls-v9_16 into v9_16
This also removes Solaris 2.8 broken gettimeofday() workaround
(cherry picked from commit e691b89a)
Closes #1679 (closed)