Seems that ignoring lack of outer_ctx serves us better. It semi-legit…

…imately-ish comes up in some cases, and ignoring those is safe enough for the time being. This fixes pre-compilation of enums (and perhaps some other bits too), and is the last known blocker for merging bs.

src/6model/serialization.c

@@ -348,9 +348,7 @@ static Parrot_Int4 get_serialized_outer_context_idx(PARROT_INTERP, Serialization
     if (!PMC_IS_NULL(VTABLE_getprop(interp, closure, Parrot_str_new_constant(interp, "COMPILER_STUB"))))
         return 0;
     if (PMC_IS_NULL(PARROT_SUB(closure)->outer_ctx))
-        Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_INVALID_OPERATION,
-            "Serialization Error: missing outer context for closure '%Ss'",
-            VTABLE_get_string(interp, closure));
+        return 0;
     return get_serialized_context_idx(interp, writer, PARROT_SUB(closure)->outer_ctx);
 }