s3: smbd: Create and use a common function for generating a fileid - create_clock_iti...

s3: smbd: Create and use a common function for generating a fileid - create_clock_itime().

This first gets the clock_gettime_mono() value, converts to an NTTIME (as
this is what is stored in the dos attribute EA), then mixes in 8 bits of
randomness shifted up by 55 bits to cope with poor resolution clocks to
avoid duplicate inodes.

Using 8 bits of randomness on top of an NTTIME gives us around 114
years headroom. We can now guarentee returning a itime-based
fileid in a normal share (storing dos attributes in an EA).

Remove knownfail.d/fileid-unique

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14928

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Christof Schmitt <cs@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Sat Jan  8 06:35:22 UTC 2022 on sn-devel-184

(cherry picked from commit 23fbf0bad0332a0ae0d4dc3c8f6df6e7ec46b88b)