This runs ember-test-audit for UI PRs to compare how long
the tests take for the base vs the PR. It posts or updates
a comparison of times and test count.
It’s somewhat slow to report back as it runs the test suite
three times to even out variability in a shared environment.
If we end up being unhappy with that slowness, we could try
running the repetitions in parallel as well, but that would
involve more changes to ember-test-audit.
This uses a fork of the Ember Asset Size Action to report on changes to
the filesizes of the production UI build as a comment to the PR. The
fork includes fixes to make it work with a subdirectory (ui/ in our
case) and to make it update the PR comment if it exists vs posting
repeatedly to the thread.
