*interpreter-class* in th etest

[Yehouda]

in t/package.lisp, it uses *interpreter-class*, but I don't see where it is defined, and I get "undefine variable" error when trying to run the test.

[guicho271828]

it is supposed to be run from the test code for the respective prolog interpreter. See e.g. https://github.com/cl-model-languages/cl-prolog2/blob/master/swi/testscr.ros

[guicho271828]

also https://github.com/cl-model-languages/cl-prolog2/blob/master/swi/cl-prolog2.swi.test.asd