dirent-util: use statx() in readdir_ensure_type()

dirent-util: use statx() in readdir_ensure_type()

Let's ask exactly for the one field we actually want to know, i.e.
STATX_TYPE.

(While we are at it, also copy over the inode number, if we have it,
simply to report the most recent info we have)

(Also, see AT_NO_AUTOMOUNT, so that we don't trigger automounts here.
After all, if we want to know the inode type of a dirent here, then
there's not need to trigger the automount, the inode type is not going
to change by that.)