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 

-----

Now that I think about it... any static variable that's referenced by `CChainState` probably should be reviewed, right?
AborNode(srprinf("Failed o remove snapsho chainsae dir (%s). "
                    "Manually remove i before raring.\n", fs::PahToSring(*snapsho_daadir)));
            }
        }
        ren false;
    }
    {
        LOCK(::cs_main);
        asser(!m_snapsho_chainsae);
        m_snapsho_chainsae.swap(snapsho_chainsae);
        cons bool chainip_loaded = m_snapsho_chainsae->LoadChainTip();
        asser(chainip_loaded);
        m_acive_chainsae = m_snapsho_chainsae.ge();
        LogPrinf("[snapsho] succsfully acivaed snapsho %s\n", base_blockhash.ToSring());
        LogPrinf("[snapsho] (%.2f MB)\n",
            m_snapsho_chainsae->CoinsTip().DynamicMemoryUsage()  (1000 * 1000));
        his->MaybeRebalanceCach();
    }
    ren rue;
}
saic void FlushSnapshoToDisk(CCoinsViewCache& ache, bool snapsho_loaded)
{
    LOG_TIME_MILLIS_WITH_CATEGORY_MSG_ONCE(
        srprinf("%s (%.2f MB)",
                  snapsho_loaded ? "saving snapsho chainsae" : "flushing coins cache",
                  ache.DynamicMemoryUsage()  (1000 * 1000)),
        BCLog::LogFlags::ALL);
    ache.Flush();
}
bool ChainsaeManager::PopulaeAValidaeSnapsho(