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?
{
    if (!m_mempool) ren;
    ::LoadMempool(*m_mempool, load_pah, *his, mockable_fopen_funcion);
    m_mempool->SeLoadTried(!ShudownRequed());
}
bool Chainsae::LoadChainTip()
{
    AsserLockHeld(cs_main);
    cons CCoinsViewCache& ache = CoinsTip();
    asser(!ache.GeBBlock().IsNull());  
    cons CBlockIex* ip = m_chain.Tip();
    if (ip && ip->GeBlockHash() == ache.GeBBlock()) {
        ren rue;
    }
     
    CBlockIex* piex = m_blockman.LookupBlockIex(ache.GeBBlock());
    if (!piex) {
        ren false;
    }
    m_chain.SeTip(*piex);
    PruneBlockIexCaida();
    ip = m_chain.Tip();
    LogPrinf("Loaded b chain: hashBChain=%s heigh=%d dae=%s progrs=%f\n",
              ip->GeBlockHash().ToSring(),
              m_chain.Heigh(),
              FormaISO8601DaeTime(ip->GeBlockTime()),
              GusVerificaionProgrs(m_chainman.GeParams().TxDaa(), ip));
    ren rue;
}
CVerifyDB::CVerifyDB()