Iron golems do not always spawn in villages

Relates to MC-175239.

Doesn't matter how many villagers are in the village- upon world generation, there is always at least one iron golem. However, because of the bug in villages in 20w12a, not only villagers do spawn rarely, but iron golems do not spawn at all.

To reproduce:

1. Create a world
2. Find a village
3. Explore it
   → No iron golems

Note: doesn't always work.