wrapper: NetBSD gives EFTYPE and FreeBSD gives EMFILE where POSIX uses ELOOP

wrapper: NetBSD gives EFTYPE and FreeBSD gives EMFILE where POSIX uses ELOOP

As documented on NetBSD's man page, open with the O_NOFOLLOW flag and a
symlink returns -1 and sets errno to EFTYPE which differs from POSIX.

This patch fixes the following test failure:

    $ sh t0602-reffiles-fsck.sh --verbose
    --- expect	2025-05-02 23:05:23.920890147 +0000
    +++ err	2025-05-02 23:05:23.916794959 +0000
    @@ -1 +1 @@
    -error: packed-refs: badRefFiletype: not a regular file but a symlink
    +error: unable to open '.git/packed-refs': Inappropriate file type or format
    not ok 12 - the filetype of packed-refs should be checked

FreeBSD has the same issue for EMLINK instead of EFTYPE.

This portability issue was introduced in cfea2f2da8 (packed-backend:
check whether the "packed-refs" is regular file, 2025-02-28)

Signed-off-by: Collin Funk <collin.funk1@gmail.com>
Acked-by: brian m. carlson <sandals@crustytoothpaste.net>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>