faccessat(2): Honor AT_SYMLINK_NOFOLLOW

Make the system call honor AT_SYMLINK_NOFOLLOW.

Also enable this from linux_faccessat2 where the issue arised the first time.
Update manual pages accordingly.

PR: 275295
Reported by: kenrap@kennethraplee.com
Approved by: kib@
Differential Revision: https://reviews.freebsd.org/D46267