PR head view doesn't show all the tests available in the individual runs

[dbaron]

I was trying to use the wpt.fyi links from the Checks tab in https://github.com/web-platform-tests/wpt/pull/43740/checks?check_run_id=21000517684 and found that the "all browsers" view doesn't show all the tests that are show in an individual browser run. In particular, comparing these two links:

• the Chrome run shows tests in accessibility/ and focus/
• the PR head view for all browsers does not show the tests in focus/

It seems like it would be useful if the second view also showed the test in focus/ so that I could link to the view of how that test did in all browsers as part of discussion of the PR.

[dbaron]

(Note that the view tied to a single revision of the PR works fine.)