Not generally, no. Even if they had access to the code at the time of review, which is hardly ever the case in my experience, there's simply no time. I also don't see a point in doing so, most papers only describe minute changes to some state of the art thing that's well established so you trust in the academic integrity and experience of authors to get that part right and usually focus on parts that matter over things like the ones this issue brings up.

Even for real reproductions, that require work just like they do in any other scientific domain, the points in that issue seem pretty irrelevant. There's things like FAIR standards on reproducibility but as far as the status quo goes that repo doesn't look too bad. I could not care less if tests for some project are badly written, at least it's in written in a non-obscure language and shows a somewhat sane structure. What's next? Calling for redactions because somebody didn't follow the same tabs vs spaces paradigm?

There's nothing in that issue w.r.t. whatever scientific finding this was used for and this general phenomenon is really fascinating. Instead of a constructive discussion with the technical or scientific folk that put their work out there, or engagement with the politicians that drew conclusions based on those scientific findings, you get github issues and Twitter threads mixing a bunch of unrelated concerns.

I’ve never heard of a reviewer writing 15K lines of code. That would be a serious undertaking for someone who is reviewing as an unpaid community service in their free time outside of doing their own research/teaching/etc.

Maybe a very dedicated reviewer might check a short simulation code that can be written in a few hours max, but even that is exceptionally rare in my experience. Reviewers usually look at the results and validation simulations in the manuscript, and if they look reasonable trust the code doesn’t have major bugs affecting accuracy.