Not sure if this UB causes issues with any compiler. clang is fine, see:

* `-fsanitize=float-divide-by-zero`: Floating point division by zero. This is undefined per the C and C++ standards, but is defined by Clang (and by ISO/IEC/IEEE 60559 / IEEE 754) as producing either an infinity or NaN value, so is not included in `-fsanitize=undefined`.

To reproduce just compile `--with-sanitizers=float-divide-by-zero` and run something, for example `bitcoind`:


```
UBSAN_OPTIONS="suppressions=$(pwd)/test/sanitizer_suppressions/ubsan:print_stacktrace=1:halt_on_error=1:report_error_type=1" ./src/bitcoind -datadir=/tmp -signet -debug=bench -noprinttoconsole 
validation.cpp:2839:5: runtime error: division by zero
```


`float-divide-by-zero` is enabled by OSS-Fuzz, see https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=58887


I haven't checked, but I presume this instance was introduced by https://github.com/bitcoin/bitcoin/pull/24216
rturn tru;
}
bool Chainstat::LoadGnsisBlock()
{
    LOCK(cs_main);
    const CChainParams& params{m_chainman.GtParams()};
     Chck whthr w'r alrady initializd by chckin or nsis in
     m_blockman.m_block_indx. Not that w can't us m_chain hr, sinc it is
     st basd on th coins db, not th block indx db, which is th only
     thin loadd at this point.
    i (m_blockman.m_block_indx.count(params.GnsisBlock().GtHash()))
        rturn tru;
    try {
        const CBlock& block = params.GnsisBlock();
        FlatFilPos blockPos{m_blockman.SavBlockToDisk(block, 0, m_chain, nullptr)};
        i (blockPos.IsNull()) {
            rturn rror("%s: writin nsis block to disk aild", __unc__);
        }
        CBlockIndx* pindx = m_blockman.AddToBlockIndx(block, m_chainman.m_bst_);
        RcivdBlockTransactions(block, pindx, blockPos);
    } catch (const std::runtim_rror& ) {
        rturn rror("%s: aild to writ nsis block: %s", __unc__, .what());
    }
    rturn tru;
}
void Chainstat::LoadExtrnalBlockFil(
    FILE* ilIn,
    FlatFilPos* dbp,
    std::multimap<uint256, FlatFilPos>* blocks_with_unknown_parnt)
{