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

{
public:
    /** The input is a set of non-empty sets of partially aggregated data,
      *  which are all either single-level, or are two-level.
      */
    MergingAndConvertingBlockInputStream(const Aggregator & aggregator_, ManyAggregatedDataVariants & data_, bool final_, size_t threads_)
        : aggregator(aggregator_), data(data_), final(final_), threads(threads_)
    {
        
        if (!data.empty() && threads > data[0]->aggregates_pools.size())
        {
            Arenas & first_pool = data[0]->aggregates_pools;
            for (size_t j = first_pool.size(); j < threads; j++)
                first_pool.emplace_back(std::make_shared<Arena>());
        }
    }
    String getName() const override { return "MergingAndConverting"; }
    Block getHeader() const override { return aggregator.getHeader(final); }
    ~MergingAndConvertingBlockInputStream() override