**Describe the bug**
```
SELECT number % 100 AS k, sumArray(emptyArrayUInt8()) AS v FROM numbers(10) GROUP BY k
```
Fails under ASan.

{
#define M(NAME) \
    else if (data_variants.type == AggregatedDataVariants::Type::NAME) \
        return prepareBlocksAndFillTwoLevelImpl(data_variants, *data_variants.NAME, final, thread_pool);
    if (false) {} 
    APPLY_FOR_VARIANTS_TWO_LEVEL(M)
#undef M
    else
        throw Exception("Unknown aggregated data variant.", ErrorCodes::UNKNOWN_AGGREGATED_DATA_VARIANT);
}
template <typename Method>
BlocksList Aggregator::prepareBlocksAndFillTwoLevelImpl(
    AggregatedDataVariants & data_variants,
    Method & method,
    bool final,
    ThreadPool * thread_pool) const
{
    auto converter = [&](size_t bucket, ThreadGroupStatusPtr thread_group)
    {
        if (thread_group)
            CurrentThread::attachToIfDetached(thread_group);
        return convertOneBucketToBlock(data_variants, method, final, bucket);
    };
    
    std::vector<std::packaged_task<Block()>> tasks(Method::Data::NUM_BUCKETS);
    try
    {