1.0.32.6: WHO-SPECIALIZES-DIRECTLY & WHO-SPECIALIZES-GENERALLY

1.0.32.6: WHO-SPECIALIZES-DIRECTLY & WHO-SPECIALIZES-GENERALLY

 * Add two new Xref functions to SB-INTROSPECT:

     WHO-SPECIALIZES-DIRECTLY returns method definitions which
     specialize one the designated class itself.

     WHO-SPECIALIZES-GENERALLY returns methods definitions which
     specialize on the designated class, or subclasses of it.

   Both take CLASS-EQ, and EQL specializers into account.

 * Refactor xref tests, and add tests for the two new functions.

 * Fix sb-introspect.asd to perform the test-op with a *D-P-D* bound
   to contrib/sb-introspect/.