Improve feedback for failing unit tests

It is often hard to identify why unit tests have failed when a rule fails to inject. Thsi can be improved in two ways:

when running Byteman intermal unit tests enable verbose trace

this will make injection failures or exceptions during parsing, type checking or execution visible to whoever is running the test

for any BMUnit test invoke the agent listener LIST functionality if the test fails

this must be done just before unloading of rules commences. it will also show the injection status of the rules, including any parse or type check errors

A further improvement is to have TransformListener.transform() dump a stack trace when a rule fails to inject correctly. This probably needs to be done at a finer level of trace than verbose so depends upon completion of BYTEMAN-294