fts: remove FTS_NOATIME
This reverts commit
da4d6974013c822af1498941e32db774b2031765.
We cannot guarantee that O_NOATIME works: e.g. openat fails
with EPERM if the effective user ID of the caller does not match
the owner of the file and the caller is not privileged.
Downstream findutils has never picked up FTS_NOATIME. Discussed at
<https://lists.gnu.org/r/bug-gnulib/2018-09/msg00122.html>.
* lib/fts_.h (FTS_NOATIME): Remove bit flag.
(FTS_OPTIONMASK): Adjust.
* lib/fts.c (diropen, fts_open, fts_build): Likewise.
(fd_ring_check): Likewise.