Fix some logic about broker load using new file scanner, with parquet format:
1. If columns are specified in load stmt, but none of them are in parquet file,
error will be thrown like `err: No columns found in file`. See `parquet_s3_case4`
2. If the first column of table are not in table, the result number of rows is wrong.
See `parquet_s3_case8`
3. If column specified in `columns` in load stmt does not exist in file and table,
error will be thrown like: `failed to find default value expr for slot: x1`. See `parquet_s3_case2`