gettimeofday, timespec_get tests: Avoid test failure on glibc/Linux. * modules/gettimeofday-tests (Depends-on): Add 'time'. * modules/timespec_get-tests (Depends-on): Likewise. * tests/test-gettimeofday.c (test_consistency): Update comment. * tests/test-timespec_get.c (main): Likewise.