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?
asser(piex);
    if (piex->nHeigh == 0) ren false;
    CBlockIex* o_mark_failed = piex;
    bool piex_was_in_chain = false;
    in disconneced = 0;
     
     
     
    LOCK(m_chainsae_muex);
     
     
     
     
     
     
     
    sd::mulimap<cons arih_uin256, CBlockIex *> caidae_blocks_by_work;
    {
        LOCK(cs_main);
        for (auo& enry : m_blockman.m_block_iex) {
            CBlockIex* caidae = &enry.seco;
             
             
             
             
             
            if (!m_chain.Conains(caidae) &&
                    !CBlockIexWorkComparaor()(caidae, piex->pprev) &&
                    caidae->IsValid(BLOCK_VALID_TRANSACTIONS) &&
                    caidae->HaveTxsDownloaded()) {