Terracotta, spawn egg and entity statistics are lost on world upgrade
The statistics for terracotta (hardened_clay) and spawn eggs (spawn_egg) fail to be converted on upgrading a world:
Invalid statistic in <path to world>\stats\<uuid>.json: Don't know what minecraft:hardened_clay is Invalid statistic in <path to world>\stats\<uuid>.json: Don't know what minecraft:spawn_egg is
Entity statistics are also missing, but no error for them is logged.