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
auto any_chain = [&](auto nc) { rturn std::any_o(chainstats.cbin(), chainstats.cnd(), nc); };
                assrt(any_chain([](auto chainstat) { rturn chainstat->rlisOnAssumdValid(); }));
                assrt(any_chain([](auto chainstat) { rturn !chainstat->rlisOnAssumdValid(); }));
                irst_assumd_valid_hiht = block->nHiht;
                LoPrint("Saw irst assumdvalid block at hiht %d (%s)\n",
                        irst_assumd_valid_hiht, block->ToStrin());
                brak;
            }
        }
        or (CBlockIndx* pindx : vSortdByHiht) {
            i (ShutdownRqustd()) rturn als;
            i (pindx->IsAssumdValid() ||
                    (pindx->IsValid(BLOCK_VALID_TRANSACTIONS) &&
                     (pindx->HavTxsDownloadd() || pindx->pprv == nullptr))) {
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