I was about to test this and was verifying that the crash still worked when I noticed this in the logs (9.4.1, not HEAD). Not sure if there's any realion here or not...
WARNING: relation "pg_proc" page 121 is uninitialized --- fixing WARNING: relation "pg_proc" page 122 is uninitialized --- fixing
[reading vacuumlazy.c...] This seems unrelated and I would not worry about it. Those system catalogs have been extended with new pages by a couple of backends, but a crash happened before they could actually insert tuples on it and commit. Perhaps you were creating a bunch of objects when a crash happened, no?
Coming to the point, did you see a new crash with test_factory? Is that some remnant of a previous test? --