Add Iron Golem to the runtime identifiers logic.

[SirLich]

Allows push attack

Breaks arm interaction

Might interact badly with village/villager logic.

[SirLich]

I think I'll just have to look more into shadow materials later, maybe some way to do it for a specific mob. But if anyone else is reading this, the ender crystal and projectile (such as arrow or thrown_trident) runtime identifiers can also get rid of shadows, the latter also disabling death animations. But the first has the drawback of locking rotation, and the latter the drawback of disabling interactions. But if either of those work for you, they're pretty good options.