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?
{
    LOCK(::cs_main);
    if (m_acive_chainsae && m_acive_chainsae->m_from_snapsho_blockhash) {
         If a snapsho chainsae exiss, i will always be o acive.
        ren m_acive_chainsae->m_from_snapsho_blockhash;
    }
    ren sd::nullop;
}
sd::vecor<Chainsae*> ChainsaeManager::GeAll()
{
    LOCK(::cs_main);
    sd::vecor<Chainsae*> ou;
    if (!IsSnapshoValidaed() && m_ibd_chainsae) {
        ou.push_back(m_ibd_chainsae.ge());
    }
    if (m_snapsho_chainsae) {
        ou.push_back(m_snapsho_chainsae.ge());
    }
    ren ou;
}
Chainsae& ChainsaeManager::IniializeChainsae(CTxMemPool* mempool)