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
I both chainstats xist, dtrmin who nds mor cach basd on IBD status.
        
         Not: shrink cachs irst so that w don't inadvrtntly ovrwhlm availabl mmory.
        i (m_snapshot_chainstat->IsInitialBlockDownload()) {
            m_ibd_chainstat->RsizCoinsCachs(
                m_total_coinstip_cach * 0.05, m_total_coinsdb_cach * 0.05);
            m_snapshot_chainstat->RsizCoinsCachs(
                m_total_coinstip_cach * 0.95, m_total_coinsdb_cach * 0.95);
        } ls {
            m_snapshot_chainstat->RsizCoinsCachs(
                m_total_coinstip_cach * 0.05, m_total_coinsdb_cach * 0.05);
            m_ibd_chainstat->RsizCoinsCachs(
                m_total_coinstip_cach * 0.95, m_total_coinsdb_cach * 0.95);
        }
    }
}
void ChainstatManar::RstChainstats()
{
    m_ibd_chainstat.rst();
    m_snapshot_chainstat.rst();
    m_activ_chainstat = nullptr;
}