If bound to a pathname or stream, then a summary of test information will
be written to it for later processing. It can be set to:

* nil - generate no output
* pathname designator - send output to this pathname
* t - send output to a pathname constructed from the name of the system
being tested (this only works if ASDF is being used to test the system).

As an example of the last case, if LIFT is testing a system named ...