platform: Allows sysfs to implement utimesns natively
This moves away from `syscall.UtimesNano` as it has intentionally
avoided common features in POSIX, such as handling UTIME_NOW and
UTIME_OMIT. When we eventually expose this API, users will be free to
override `UTIME_NOW` with a fake clock, possibly the same that was
supplied to wazero's `ModuleConfig`.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
Co-authored-by: Edoardo Vacchi <evacchi@users.noreply.github.com>
