[python] optimize logic to add pylint disable for line-too-long

[msyyc]

Python emitter now has much logic to add single-line pylint disable for line-too-long in multi files. It is hard to maintain. And I think we could check it in last black part. In black part, we could get final result of generated code then if there is too long line, we could add pylint disable in head of the file. (e.g. here)