s3: tests: Add a new test test_msdfs_hardlink() that does simple hardlinks on MSDFS...

s3: tests: Add a new test test_msdfs_hardlink() that does simple hardlinks on MSDFS root shares.

We pass this already as the cmd_hardlink in smbclient doesn't
do the DFS path conversion on the hardlink target. But it's
good to have the test.

Note we need to add the new test to "selftest/knownfail.d/smb1-tests"
as test_smbclient_s3.sh is run against the (ad_member|nt4_member)
environments first using NT1 (SMB1) protocol and then using SMB3,
but the (ad_member|nt4_member) environments don't support SMB1.
Seems a bit strange to me, but all the other SMB1 tests inside
test_smbclient_s3.sh have already been added to "selftest/knownfail.d/smb1-tests"
so just go with the test environment.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14169

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Noel Power <npower@samba.org>