Message 300468 - Python tracker

As covered in issue 31183, correctly disassembling functions, generator-iterators, coroutines, and async generator-iterators currently requires checking for 4 different attributes:

* __code__ (functions)
* gi_code (generator iterators)
* cr_code (coroutines)
* ag_code (async generator iterators)

This could be simplified if the latter three all *also* exposed their code attributes as `__code__`.