[MC-214866] Superflat worlds customization does not support negative hights

Superflat worlds customization does not support negative hights. It always starts with 0.

Set any layer in superflat customization. It is impossible to generate blocks below y=0.

Linked issues

I can't confirm – when generating a default superflat world, the layers generate starting at -64. Am I misunderstanding this issue?

I... can no longer reproduce the issue too. It "worked" just a second ago.