Raid ends as defeats when a single villager loses its job.

Note: I do not know if this is an intended feature or not.

To reproduce:

1. Find a single villager with no other villagers around.
2. Give him a job block and let him take the job block. (Do not trade with the villager.)
3. Start a raid.
4. Destroy the job block which the villager took. (My villager lost its job suddenly.)