**Describe the bug**
```
clickhouse-client --max_block_size 123 -n < 01130_in_memory_parts_nested.sql
```

Outputs an array with huge number of zeros that is definitely incorrect.
#include <Storages/MergeTree/MergeTreeReaderInMemory.h>
#include <Storages/MergeTree/MergeTreeDataPartInMemory.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/NestedUtils.h>
#include <Columns/ColumnArray.h>
#include <Poco/File.h>
namespace DB
{
namespace ErrorCodes
{
    extern const int CANNOT_READ_ALL_DATA;
    extern const int ARGUMENT_OUT_OF_BOUND;
}
MergeTreeReaderInMemory::MergeTreeReaderInMemory(