Fix bug when reading array type in parquet file:
```
ERROR 1105 (HY000): errCode = 2, detailMessage = [INTERNAL_ERROR]Read parquet file xxx failed,
reason = [IO_ERROR]Decode too many values in current page
```
When reading normal columns, `ScalarColumnReader::_read_values` still calls `ColumnSelectVector::set_run_length_null_map` to initialize select vector, but `ScalarColumnReader::_read_nested_column` hasn't do this, making the number of values wrong.
The situation where this error occurs is particularly extreme: The column pages have remaining values to be read,
but all of them are null values at ancestor level, so there's no actual read operation, just skipping null values at ancestor level.
39d66ca2c6