r3608: added BASE-DENYDOS test

r3608: added BASE-DENYDOS test

this test demonstrates how w2k3 handles the special semantics of
DENY_DOS when 2 opens happen on the same connection. The 2nd open
doesn't actually do a NTFS open, it happens as a secondary reference
to the same internal file handle in the CIFS layer. The evidence is
that the 2nd open shares the same POSITION_INFORMATION field as the
first open, but only for the special DENY_DOS cases that would
normally be refused.
(This used to be commit eeec57d4f6d18a40e0ce451bfe051b3f699e8337)