testsuite/libsmbclient: Remove unused and expensive-to-link testsuite

testsuite/libsmbclient: Remove unused and expensive-to-link testsuite

This testsuite never got off the ground, and unlike the other
libsmbclient tests, it is not integrated into make test, has no driver
script we could integrate.

As it has been in this state for 10 years, and adding it to the compile
did not find any link-time issues (particularly in comparison to the
link-time cost for so many individual binaries), I am now removing them.

The libsmbclient examples are seperate to this, and remain in
examples/libsmbclient.

Andrew Bartlett