Convention of Metadata Placement

At byte 80 of [alltypes_dictionary](https://github.com/apache/parquet-testing/blob/master/data/alltypes_dictionary.parquet), there is another instance of the column_chuck metadata. This does not seem to be consistent with other parquet files and the convention of this seems to go against the [canonical spec](https://parquet.apache.org/docs/file-format/data-pages/columnchunks/) where all column chunks should be written back to back and be separate from the metadata itself.