[MC-171020] New nether biomes don't work properly in buffet worlds

The bug

The new nether biomes (nether wastes, soul sand valley, crimson forest, warped forest and basalt deltas) do not work in Surface or Floating Island Buffet worlds.

To reproduce

Create New World
Select More World Options
Make a buffet world
Select Soul Sand Valley
Set terrain type to Floating Islands or Surface
→ Floating Island mode Freezes the game before it even loads terrain (Image Below)
→ -Surface mode creates a purely ocean world (This happened the first time i tried to make one but works fine now for some reason)

The following list is updated in version 20w15a:

Biomes	All world generators that freeze the game
Nether wastes	Surface
Crimson forest	Surface
Warped forest	Surface and floating islands
Soul sand valley	Surface
Basalt deltas	Surface