Support `Collection` types

`List_` types are explicitly supported in `util.py`, where:

- `type_contains_serialized_data` function returns whether the extracted type contains serialized data
- `item_type` function returns a transformed version of the extracted type
- `is_var_sized_list` function returns if it it's a list and not in `FixSizedListTypes`

`Collection` has no such support, and when a `Collection_Something` type is used, the following is logged:
```Binary compatibility tests cannot be generated. Error: 'NoneType' object is not callable```