**Describe the bug**
https://clickhouse-test-reports.s3.yandex.net/19702/c74631c650b42e4d107254a03bd82c2c2913039b/fuzzer_msan/server.log

Most likely introduced here: #11006
{
    for (size_t offset = 0; offset < size; offset += 16)
    {
        uint16_t mask = _mm_movemask_epi8(_mm_cmpeq_epi8(
            _mm_loadu_si128(reinterpret_cast<const __m128i *>(a + offset)),
            _mm_loadu_si128(reinterpret_cast<const __m128i *>(b + offset))));
        mask = ~mask;
        if (mask)
        {
            offset += __builtin_ctz(mask);
            return detail::cmp(a[offset], b[offset]);
        }
    }
    return 0;
}
/** Variant when the size is 16 exactly.
  */
template <typename Char>
inline int memcmp16(const Char * a, const Char * b)