Initial fix for support for running cl-bench test suite from Ant build via ASDF.
This probably doesn't work on win32 without 'make' in your path.
Running the cl-bench suite now works via the 'test.cl-bench' target if
the test suite has been downloaded from
"http://www.chez.com/emarsden/downloads/cl-bench.tar.gz" and placed in
a sibling directory (#p../cl-bench/) to ABCL root.
Move the cl-bench ASDF description into 'abcl.asd' now that I have
finally understood (?) the correct CLOS method invocation.