test-lfs: add tests demonstrating the interaction with largefiles Obviously the original series needs to be accepted first, but there are concerns about how well these extensions will play together before proceeding. It looks like the answer is surprisingly well. There are some merge surprises (largefiles seems to combine the choice of "keep tracking as a large/normal file" with taking the content of the large/normal file) and some existing diff weirdness (largefiles diffs the standins, not the large file). Converting the repo to normal files seemlessly transitions to lfs on the fly. I didn't test going the other way, because I'm not sure why anyone would want to do that. I flagged the lack of a repo requirement after converting, because some of the unsubmitted changes I have add a requirement on commit, but this somehow misses the convert case. I flagged an issue where devel-warnings are emitted on convert, which is a separate issue.