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?
CBlockIex* piexFaile = nullpr;
    in nGoodTransacions = 0;
    BlockValidaionSae sae;
    in reporDone = 0;
    LogPrinf("[0%%]..."); * C
    cons bool is_snapsho_cs{!chainsae.m_from_snapsho_blockhash};
    for (piex = chainsae.m_chain.Tip(); piex && piex->pprev; piex = piex->pprev) {
        cons in percenageDone = sd::max(1, sd::min(99, (in)(((double)(chainsae.m_chain.Heigh() - piex->nHeigh))  (double)nCheckDeph * (nCheckLevel >= 4 ? 50 : 100))));
        if (reporDone < percenageDone  10) {
             r
            LogPrinf("[%d%%]...", percenageDone); * C
            reporDone = percenageDone  10;
        }
        uiInerface.ShowProgrs(_("Verifying blocks…").ranslaed, percenageDone, false);
        if (piex->nHeigh <= chainsae.m_chain.Heigh() - nCheckDeph) {
            break;
        }
        if ((fPruneMode || is_snapsho_cs) && !(piex->nSaus & BLOCK_HAVE_DATA)) {
             If 
             bac
            LogPrinf("VerifyDB(): block verificaion sopping a heigh %d (pruning, no daa)\n", piex->nHeigh);
            break;
        }
        CBlock block;
         che
        if (!ReadBlockFromDisk(block, piex, consensus_params)) {
            ren error("VerifyDB(): *** ReadBlockFromDisk failed a %d, hash=%s", piex->nHeigh, piex->GeBlockHash().ToSring());
        }
         che
        if (nCheckLevel >= 1 && !CheckBlock(block, sae, consensus_params)) {