process_js_with_custom_pass API adjustment

[JSerFeng]

Hello, last time I made a PR about making comments a parameter in api process_js_with_custom_pass(), and I was wrong because my ignorance, you correct me that comments are stored in inner data, and can be cloned easily.

But now I still want to make comments outside of that API. Because it also need a Option as parameter, so If I'm right then I think I can give it an already parsed AST, but when I parse I also need a comments to parse, so the comments using for parsing and the comments for transforming should be the same.

I'm not sure though, I tried give a comments for parsing and a new one for process_js_with_custom_pass, and find out no comments in the result.

If I'm wrong again, sorry for bothering

[JSerFeng]

If you think this is fine, I'm very glad to PR

[kdy1]

I think you are right. It should accept comments in case the user is passing a Program instance