> This is another intermediate part of the Coinstats Index (tracked in core#18000).
>
> Sjors suggested here that the part of the changes in #19145 that don't rely on the new hash_type muhash, i.e. that are for hash_type=none, could be merged separately from everything involving muhash. So these changes are extracted from #19145 here and can be merged without any other requirements.
>
> Building the index with no UTXO set hash is still valuable because gettxoutsetinfo can still be used to audit the total_amount for example. By itself this PR is not a huge improvement, hash_type=none is speeding up gettxoutsetinfo by about 10%, but it enables the implementation of an index on top of it in a follow-up and that means large parts of the index code of Coinstats Index can be merged while reviews for the hashing algorithm might take longer.
This is a backport of core#19328 [1/4]
https://github.com/bitcoin/bitcoin/pull/19328/commits/605884ef21318fc3f326dbdf4901cb353ba63fab