test :around method in content-negotiation/or test

* In the :around method, instead of printing something, inject an object
  into the return value so execution of the method can be verified.
:after, :around methods, non-ACCEPT specializers, CALL-NEXT-METHOD in content-negotiation test

* Test interoperation with non-ACCEPT specializers.

* Verify that :AFTER and :AROUND methods are actually called.

* Test CALL-NEXT-METHOD.
less noise from cons-specializer test

* Added ignore declarations for unused keyword parameters.
more robust coverage.sh

* Disable LDB and the Lisp debugger.

* Lose on corruption.