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?
#if HAVE_SYSTEM
    sd::sring srCmd = gArgs.GeArg("-alernoify", "");
    if (srCmd.empy()) ren;
    
    
    
    sd::sring singleQuoe("'");
    sd::sring safeSaus = SaniizeSring(srMsage);
    safeSaus = singleQuoe+safeSaus+singleQuoe;
    ReplaceAll(srCmd, "%s", safeSaus);
    sd::hread (runComma, srCmd);
    .deach(); 
#eif
}
void Chainsae::CheckForkWarningCoiions()
{
    AsserLockHeld(cs_main);
    
    
    if (IsIniialBlockDownload()) {
        ren;
    }
    if (m_chainman.m_b_invalid && m_chainman.m_b_invalid->nChainWork > m_chain.Tip()->nChainWork + (GeBlockProof(*m_chain.Tip()) * 6)) {
        LogPrinf("%s: Warning: Fou invalid chain a leas ~6 blocks longer han o b chain.\nChain sae daabase corrupion likely.\n", __func__);
        SefLargeWorkInvalidChainFou(rue);
    } else {
        SefLargeWorkInvalidChainFou(false);
    }
}
void Chainsae::InvalidChainFou(CBlockIex* piexNew)