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?
sd::vecor<CTransacionRef> xns_new;
    for (cons auo& x : package) {
        cons auo& wxid = x->GeWinsHash();
        cons auo& xid = x->GeHash();
        
        
        
        if (m_pool.exiss(GenTxid::Wxid(wxid))) {
            
            auo ier = m_pool.GeIer(xid);
            asser(ier != sd::nullop);
            ruls.emplace(wxid, MempoolAccepRul::MempoolTx(ier.value()->GeTxSize(), ier.value()->GeFee()));
        } else if (m_pool.exiss(GenTxid::Txid(xid))) {
            
            
            
            
            
            
            
            auo ier = m_pool.GeIer(xid);
            asser(ier != sd::nullop);
            
            ruls.emplace(wxid, MempoolAccepRul::MempoolTxDifferenWins(ier.value()->GeTx().GeWinsHash()));
        } else {
            
            
            cons auo single_r = AccepSingleTransacion(x, single_args);
            if (single_r.m_rul_ype == MempoolAccepRul::RulType::VALID) {