Recently I built this: Although, after waiting for 36000+ ticks, no iron golems are spawning. I am well aware I don't have a 1:1 ratio of beds to villagers but this shouldn't matter.
What I have tried (in a creative testing world): add more villagers, remove water and some various other things here and there. So what requirement am I missing out for these iron golems to spawn? I sieved through the Minecraft wiki page on iron golems and seem to be meeting each requirement.
World Download (Named Survival: Can be switched to creative by opening up the world to LAN and turning cheats on)