Hide detailed failure output in scripts/fiber/record-tests

[sophiebits]

[cpojer]

I think this is fine but I feel like adding a flag for this in Jest (opposite of --verbose) would have been simpler than this :D

[sophiebits]

Thanks. I was actually in the middle of writing a test runner wrapper for another reason (to hackily split out "passing" from "passing except dev warnings" from "failing") and once I got here I realized that it was just one line (.failureMessage = null) to get this to work.