`stat` only provide timestamp down to second instead of nanosecond

Description

Hi maintainer,

stat in php only provide presicion down to second, but it could be down to nanosecond.

  File: abc.xyz
  Size: 0         	Blocks: 0          IO Block: 4096   regular empty file
Device: 8,2	Inode: 6160531     Links: 1
Access: (0664/-rw-rw-r--)  Uid: ( 0/root)   Gid: ( 0/root)
Access: 2023-08-12 09:10:14.152726478 +0700
Modify: 2023-08-12 09:10:14.152726478 +0700
Change: 2023-08-12 09:10:14.152726478 +0700
 Birth: 2023-08-12 09:10:14.152726478 +0700

[
  ...,
  "atime" => 1691806214,
  "mtime" => 1691806214,
  "ctime" => 1691806214,
  ...
]

I'm aware that https://linux.die.net/man/2/stat does explain it Since kernel 2.5.48, the stat structure supports nanosecond resolution for the three file timestamp fields..

I was running into this problem today, run test need to ensure directory was created within 1s, which cannot be done if read from php stat.

La issue cita l'API stat di PHP e i timestamp stat di Linux con supporto ai nanosecondi, ma non indica alcun file sorgente né alcun test. Inizia individuando l'implementazione PHP e i test esistenti per i campi dei timestamp di stat, quindi confronta i relativi valori con i timestamp del filesystem mostrati da Linux stat. Il lavoro è completato quando PHP espone la precisione al di sotto del secondo disponibile e il comportamento è coperto da test.