Validate remaining language codes

[berrymot]

• art-loglan and art-guaspi are missing an `x-' after the hyphen
• en-bpfk's bpfk is four letters long and therefore treated as a script Bpfk, but no script with that code exists; to fix, add a letter somewhere
• fr-facile: change to fr-simple I guess
• test: turns out x-test is valid by itself