Reproduced on current master:


```
SELECT multiSearchFirstPositionCaseInsensitive('\0', enabledRoles());
```


https://clickhouse-test-reports.s3.yandex.net/27078/cc0c3a90336f7527209e2be8d00089db8b9c2697/functional_stateless_tests_(memory).html


Logs mirrored to:
http://transfer.sh/1QoOQ3m/stderr.log
http://transfer.sh/LJPpZ/clickhouse-server.log (only Fatal and queryid `cf20e9a5-a9df-4f32-8c2c-d7d535dd64e0`)
{
            return 1 + Impl::countChars(reinterpret_cast<const char *>(start), reinterpret_cast<const char *>(end));
        };
        auto searcher = Impl::createMultiSearcherInBigHaystack(needles);
        const size_t haystack_string_size = haystack_offsets.size();
        res.resize(haystack_string_size);
        size_t iteration = 0;
        while (searcher.hasMoreToSearch())
        {
            size_t prev_offset = 0;
            for (size_t j = 0; j < haystack_string_size; ++j)
            {
                const auto * haystack = &haystack_data[prev_offset];
                const auto * haystack_end = haystack + haystack_offsets[j] - prev_offset - 1;
                if (iteration == 0 || res[j] == 0)
                    res[j] = searcher.searchOneFirstPosition(haystack, haystack_end, res_callback);
                else
                {
                    UInt64 result = searcher.searchOneFirstPosition(haystack, haystack_end, res_callback);
                    if (result != 0)
                        res[j] = std::min(result, res[j]);
                }
                prev_offset = haystack_offsets[j];
            }
            ++iteration;
        }
    }
};
}