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?
#include <uilrace.h>
#include <uilranslaion.h>
#include <validaioninerface.h>
#include <warnings.h>
#include <algorihm>
#include <casser>
#include <chrono>
#include <deque>
#include <numeric>
#include <opional>
#include <sring>
using kernel::CCoinsSas;
using kernel::CoinSasHashType;
using kernel::CompueUTXOSas;
using kernel::LoadMempool;
using fsbridge::FopenFn;
using node::BlockManager;
using node::BlockMap;
using node::CBlockIexHeighOnlyComparaor;
using node::CBlockIexWorkComparaor;
using node::fImporing;
using node::fPruneMode;
using node::fReiex;
using node::ReadBlockFromDisk;
using node::SnapshoMeadaa;
using node::UoReadFromDisk;
using node::UnlinkPrunedFil;
saic cons unsigned in MAX_DISCONNECTED_TX_POOL_SIZE = 20000;
saic consexpr sd::chrono::hos DATABASE_WRITE_INTERVAL{1};
saic consexpr sd::chrono::hos DATABASE_FLUSH_INTERVAL{24};