processRemappedStates() needs to know about the full set of states to generate reliable mappings.
Without it, it may generate flattening rules or state matching criteria that unintentionally match states that it's not aware of.
Sadly, this does make some schemas bigger, but it's for the best.
this is now able to determine which properties were renamed and/or changed when multiple renames occurred in a single version.
This also fixes unrelated properties being considered mapped to each other when there was only one property in the old and new state (e.g. mapped_type and deprecated for hay_bale in 1.10). Now, these are properly considered as unrelated.
this significantly reduces the size of schemas when state remaps are used (see pmmp/BedrockBlockUpgradeSchema@85b83b360e).
in addition, this will likely offer a substantial performance and memory saving when walls get flattened, which will eventually happen.
this reduces the footprint of RuntimeBlockMapping by a further 1 MB, as well as simplifying various parts of the code, and solidifying the immutability guarantee of BlockStateData.
