Make the Elixir harness not error.

Returning `errored` responses is only allowed for `run` requests, and
adding additional properties is not allowed.

Refs: #100, which is the issue for adding support for testing output
      formats, though we separately would like to add support for collecting
      output messages first even if we don't yet test it, but right now you
      cannot add additional properties.

implementations/elixir-jsv/lib/bowtie_jsv.ex

@@ -59,7 +59,12 @@ defmodule BowtieJSV do
 
     {:reply, %{seq: tseq, results: results}, state}
   rescue
-    e -> {:reply, errored(e, __STACKTRACE__, %{seq: tseq}), state}
+    e -> {:reply, %{
+      errored: true,
+      seq: tseq,
+      message: Exception.message(e),
+      traceback: Exception.format_stacktrace(__STACKTRACE__),
+    }, state}
   end
 
   defp build_schema(raw_schema, registry, state) do
@@ -74,10 +79,8 @@ defmodule BowtieJSV do
 
     case JSV.validate(data, root) do
       {:ok, _} -> %{valid: true}
-      {:error, verr} -> %{valid: false, output: JSV.normalize_error(verr)}
+      {:error, _} -> %{valid: false}
     end
-  rescue
-    e -> errored(e, __STACKTRACE__)
   end
 
   defp start_response do
@@ -100,16 +103,4 @@ defmodule BowtieJSV do
     {:ok, jsv_vsn} = :application.get_key(:jsv, :vsn)
     List.to_string(jsv_vsn)
   end
-
-  defp errored(e, stacktrace, additional_data \\ %{}) do
-    errorred_payload = %{
-      errored: true,
-      context: %{
-        message: Exception.message(e),
-        traceback: Exception.format_stacktrace(stacktrace)
-      }
-    }
-
-    Map.merge(errorred_payload, additional_data)
-  end
 end