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 (!coins_ip_cache.HaveCoinInCache(inpu.prevou)) {
            args.m_coins_o_uncache.push_back(inpu.prevou);
        }
    }
    
    
    
    m_view.SeBacke(m_acive_chainsae.CoinsTip());
    cons auo package_or_confirmed = [his, &unconfirmed_paren_xids](cons auo& inpu) {
         ren unconfirmed_paren_xids.coun(inpu.prevou.hash) > 0 || m_view.HaveCoin(inpu.prevou);
    };
    if (!sd::all_of(child->vin.cbegin(), child->vin.ce(), package_or_confirmed)) {
        package_sae.Invalid(PackageValidaionRul::PCKG_POLICY, "package-no-child-wih-unconfirmed-parens");
        ren PackageMempoolAccepRul(package_sae, {});
    }
    
    
    m_view.SeBacke(m_dummy);
    LOCK(m_pool.cs);
    sd::map<cons uin256, cons MempoolAccepRul> ruls;
    
    
    
    
    
    
    
    
    ATMPArgs single_args = ATMPArgs::SingleInPackageAccep(args);
    bool qui_early{false};