Fix Biomes

[Owen1212055]

Because worlds can now have their height adjusted biomes are now able to change size. BiomeStorage.a used to be 256 as this was when biomes were 2D. However due to the biome format changing and height things this constant has changed. It represents the MAXIMUM amount of biome data that can be held... uh oh.

This caused biomes to use A LOT of memory because it was setting the biome data to as large as possible.

We now however use the chunk biome container constructor directly. Using a custom BiomeSource object (spigot calls it a WorldChunkManager) we simply make it always return the default value.

public ChunkBiomeContainer(IdMap<Biome> biomes, LevelHeightAccessor world, ChunkPos chunkPos, BiomeSource biomeSource, @Nullable int[] aint) {
        this(biomes, world, new Biome[(1 << ChunkBiomeContainer.WIDTH_BITS + ChunkBiomeContainer.WIDTH_BITS) * ChunkBiomeContainer.ceilDiv(world.getHeight(), 4)]);
        int i = QuartPos.fromBlock(chunkPos.getMinBlockX());
        int j = this.quartMinY;
        int k = QuartPos.fromBlock(chunkPos.getMinBlockZ());

        for (int l = 0; l < this.biomes.length; ++l) {
            if (aint != null && l < aint.length) {
                this.biomes[l] = (Biome) biomes.byId(aint[l]);
            }

            if (this.biomes[l] == null) {
                this.biomes[l] = ChunkBiomeContainer.generateBiomeForIndex(biomeSource, i, j, k, l);
            }
        }

    }

The world format should not need to be changed. As the length of biomes is stored in the world data.