Refactor for better handling of `cuModuleLoadDataEx`/`cuLibraryLoadData`

[leofang]

This is a bit trickier than I thought, because we also need the dict key "old"/"new" as a proxy to prepare for args (which is different for cuModuleLoadDataEx/cuLibraryLoadData). Let's improve this after beta 1.

Originally posted by @leofang in #188 (comment)