MR does not show legacy diff notes on the changes tab any more

First, import https://github.com/gitlab-qa/test-project (there are credentials in 1Password under GitLab QA).

In 10.8, if you loaded the changes tab, those changes were shown:

This is a little odd, because on the discussion tab, they showed as appearing on a commit:

In 11.1, they show on the discussion tab (following https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/20214), but not on the changes tab.