generateRandom() does not support generating random Date32 value:

```
SELECT *
FROM generateRandom('Date32 Date32', NULL, 10, 2)
LIMIT 10

Received exception from server (version 21.11.5):
Code: 48. DB::Exception: Received from localhost:9000. DB::Exception: The 'GenerateRandom' is not implemented for type Date32: While executing GenerateRandom. (NOT_IMPLEMENTED)
```

const Names & column_names,
    const StorageMetadataPtr & metadata_snapshot,
    SelectQueryInfo & ,
    ContextPtr context,
    QueryProcessingStage::Enum ,
    size_t max_block_size,
    unsigned num_streams)
{
    metadata_snapshot->check(column_names, getVirtuals(), getStorageID());
    Pipes pipes;
    pipes.reserve(num_streams);
    const ColumnsDescription & our_columns = metadata_snapshot->getColumns();
    Block block_header;
    for (const auto & name : column_names)
    {
        const auto & name_type = our_columns.get(name);
        MutableColumnPtr column = name_type.type->createColumn();
        block_header.insert({std::move(column), name_type.type, name_type.name});
    }
    
    pcg64 generate(random_seed);
    for (UInt64 i = 0; i < num_streams; ++i)
        pipes.emplace_back(std::make_shared<GenerateSource>(max_block_size, max_array_length, max_string_length, generate(), block_header, context));
    return Pipe::unitePipes(std::move(pipes));
}
}