Portion of diff was dropped in the mappings update commit.
Also remove the option to remove invalid statistics. The server will
automatically do this now as of... 1.13?, our option wasn't even doing anything.
Minecraft is trying to set Dimension Objects based on a Dimension ID
Dimension ID's for custom worlds are dynamically allocate dand not guaranteed
consistent.
This removes checking the NBT data, as the Entity will always have its
DimensionManager set to the world it is being placed into.
This fixes corrupt entities breaking chunk saving in custom worlds.