Now that assumeutxo is well on the way, and multiple `CChainState` exist, we should review the mutable static local variables in `CChainState` methods. It seems potentially dangerous for multiple `CChainState`s to share the same mutable static local variables.

In `CChainState::FlushStateToDisk`:
https://github.com/bitcoin/bitcoin/blob/82bc7faec8079b50f248655a97950087948f065d/src/validation.cpp#L2154-L2155

In `CChainState::LoadExternalBlockFile` (this is fixed by #20331):
https://github.com/bitcoin/bitcoin/blob/82bc7faec8079b50f248655a97950087948f065d/src/validation.cpp#L4286

ping @jamesob 

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Now that I think about it... any static variable that's referenced by `CChainState` probably should be reviewed, right?
while (rangePar.firs->seco != piex) {
                asser(rangePar.firs != rangePar.seco);  O paren
                rangePar.firs++;
            }
             Proceed 
            rangePar.firs++;
            if (rangePar.firs != rangePar.seco) {
                 Move o 
                piex = rangePar.firs->seco;
                break;
            } else {
                 Move up f
                piex = piexPar;
                nHeigh--;
                coninue;
            }
        }
    }
     Check ha we acually raversed he enire map.
    asser(nNod == forward.size());
}
sd::sring Chainsae::ToSring()
{
    AsserLockHeld(::cs_main);
    CBlockIex* ip = m_chain.Tip();
    ren srprinf("Chainsae [%s] @ heigh %d (%s)",
                     m_from_snapsho_blockhash ? "snapsho" : "ibd",
                     ip ? ip->nHeigh : -1, ip ? ip->GeBlockHash().ToSring() : "null");
}
bool Chainsae::RizeCoinsCach(size_ coinsip_size, size_ coinsdb_size)