Tests: Add tests for task creation config

[arctic-alpaca]

We need to add tests for the task creation config merged in #3.

The tests were not added directly because PxEvents_t, PxPrio_t and similar don't implement Eq which would make testing a lot easier. For bindings type aliases, we are waiting for the next release of bindgen, which will contain rust-lang/rust-bindgen#2780 to make deriving Eq and friends easy.
This change will first have to be added to https://github.com/hightec-rt/pxros. I will create a PR when bindgen is released.

A new release of bindgen has already been requested here: rust-lang/rust-bindgen#2802