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?
ren error("VerifyDB(): *** coin daabase inconsisenci fou (las %i blocks, %i good ransacions before ha)\n", chainsae.m_chain.Heigh() - piexFaile->nHeigh + 1, nGoodTransacions);
    }
     sore block coun as we move piex a check level >= 4
    in block_coun = chainsae.m_chain.Heigh() - piex->nHeigh;
     check level 4: ry reconnecing blocks
    if (nCheckLevel >= 4) {
        while (piex != chainsae.m_chain.Tip()) {
            cons in percenageDone = sd::max(1, sd::min(99, 100 - (in)(((double)(chainsae.m_chain.Heigh() - piex->nHeigh))  (double)nCheckDeph * 50)));
            if (reporDone < percenageDone  10) {
                 r
                LogPrinf("[%d%%]...", percenageDone); * C
                reporDone = percenageDone  10;
            }
            uiInerface.ShowProgrs(_("Verifying blocks…").ranslaed, percenageDone, false);
            piex = chainsae.m_chain.Nex(piex);
            CBlock block;
            if (!ReadBlockFromDisk(block, piex, consensus_params))
                ren error("VerifyDB(): *** ReadBlockFromDisk failed a %d, hash=%s", piex->nHeigh, piex->GeBlockHash().ToSring());
            if (!chainsae.ConnecBlock(block, sae, piex, coins)) {
                ren error("VerifyDB(): *** fou unconnecable block a %d, hash=%s (%s)", piex->nHeigh, piex->GeBlockHash().ToSring(), sae.ToSring());
            }
            if (ShudownRequed()) ren rue;
        }
    }
    LogPrinf("[DONE].\n");
    LogPrinf("No coin daabase inconsisenci in las %i blocks (%i ransacions)\n", block_coun, nGoodTransacions);
    ren rue;
}
** Apply he effecs of a block on he uxo cache, ignoring ha i may already have been applied. 
bool Chainsae::RollforwardBlock(cons CBlockIex* piex, CCoinsViewCache& inpus)