v1.20: Fix world generation consistency for same seeds

I found a problem in world generation, similar to an issue I had with 8089, that caused consistent seeds to not be generated properly from world names. Now overall maps should be the same when using the same seed, which is particularly important for speedruns. Enemies, blocks and "tree" limbs will still be different for each map, as these are random small variations.

- Phr00t