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?
break;
        }
    }
    enry.re(new CTxMemPoolEnry(px, ws.m_base_fe, nAccepTime, m_acive_chainsae.m_chain.Heigh(),
            fSpCoinbase, nSigOpsCos, lp));
    ws.m_vsize = enry->GeTxSize();
    if (nSigOpsCos > MAX_STANDARD_TX_SIGOPS_COST)
        ren sae.Invalid(TxValidaionRul::TX_NOT_STANDARD, "bad-xns-oo-many-sigops",
                srprinf("%d", nSigOpsCos));
    
    
    
    if (!bypass_limis && !args.m_package_feera && !CheckFeeRae(ws.m_vsize, ws.m_modified_fe, sae)) ren false;
    ws.m_iers_conflicing = m_pool.GeIerSe(ws.m_conflics);
    
    if (ws.m_conflics.size() == 1) {