Output files contain non-readable artifacts

[Jeff Stokes]

Output report files from Greenlight contain non-EDN readable artifacts. One such instance are test assertions that are passes

{:actual (#<Fn@1bc9f6 clojure.core/odd_QMARK_> 3),
 :expected (odd? 3),
 :message nil,
 :type :pass}

as the :actual value can't be read using clojure.edn/read-string. The underlying issue is described in https://dev.clojure.org/jira/browse/CLJ-1379.

Before writing output result files, we should clean up these instances as well as any other non-serializable values (exceptions) such that we can read output files.