x/build: luci test results hidden in aborted parallel tests

[rsc]

This display shows tons of failed tests unexpectedly aborted but only one test that actually failed (with a throw, breaking all the other parallel tests): https://ci.chromium.org/ui/inv/build-8756813787079044929/test-results?sortby=&groupby=

"Expand All and scroll" works OK for finding the culprit but it would be nice if it was highlighted better, like maybe hiding the unexpected aborts when there is a clear failure too