Improve Unit Test Coverage of Parquet -> Arrow Converter

[tustvold]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

#1682 added new logic for the parquet -> arrow schema conversion, and relied on the existing test coverage in schema.rs to validate this. However, these tests only validate the type conversions, and not the definition/repetition levels. It would be good to add some additional test coverage to cover this

Describe the solution you'd like

Unit tests within the complex.rs module

Additional context

Suggested by @alamb https://github.com/apache/arrow-rs/pull/1682/files/e2f12dedaac3d7cc0ce95cec504ff87e26d6cf4f#r871363997