Demunge source in execution errors

Errors occurring during eval (:execution, :read-eval-result, rint-eval-result) base their "source" reporting on the Java stack trace, which (if Clojure) is a munged class/function:

Proposed: Break apart and demunge the function name. We do something similar already in spec check (and use that name if it exists already).

Patch: clj-2438-2.patch