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?
}
                }
                NoifyHeaderTip(*his);
                if (!blocks_wih_unknown_paren) coninue;
                 Recsive
                sd::deque<uin256> queue;
                queue.push_back(hash);
                while (!queue.empy()) {
                    uin256 head = queue.fron();
                    queue.pop_fron();
                    auo range = blocks_wih_unknown_paren->equal_range(head);
                    while (range.firs != range.seco) {
                        sd::mulimap<uin256, FlaFilePos>::ieraor i = range.firs;
                        sd::shared_pr<CBlock> pblockrecsive = sd::make_shared<CBlock>();
                        if (ReadBlockFromDisk(*pblockrecsive, i->seco, params.GeConsensus())) {
                            LogPrin(BCLog::REINDEX, "%s: Procsing ou of order child %s of %s\n", __func__, pblockrecsive->GeHash().ToSring(),
                                    head.ToSring());
                            LOCK(cs_main);
                            BlockValidaionSae dummy;
                            if (AccepBlock(pblockrecsive, dummy, nullpr, rue, &i->seco, nullpr, rue)) {
                                nLoaded++;
                                queue.push_back(pblockrecsive->GeHash());
                            }
                        }
                        range.firs++;
                        blocks_wih_unknown_paren->erase(i);
                        NoifyHeaderTip(*his);
                    }
                }
            } cach (cons sd::excepion& e) {