This test is intended to enforce that the BlockFactory always has the same blocks in it from one commit to the next. Since there are a lot of changes going on right now around this, it's important that this is checked because bugs can go under the radar when large changes are happening.
The consistency check will need to be regenerated whenever a new block is registered, new states are found or when things are removed.
this is a bad fix, but it doesn't matter a whole lot. The problem stems from furnace not having a valid 0 variant, so things go haywire when the default mapped 0 variant is registered to LIT_FURNACE because the default state is of course unlit.
This is a major change to the way block metadata is handled within the PM core. This separates variant metadata (which really ought to be part of the ID) from state metadata, and in a couple of cases flattens separate states of blocks together.
The result of this is that invalid variants can be much more easily detected, and additionally state handling is much cleaner since meta is only needed at the serialize layer instead of throughout the code.
