1c19fe8d81 isn't sufficient for local files, because detection is run
twice, so a translator may not be available when the detect callback is
run. This changes the test to poll for the translate icon, which is a
bit of a hack but does the job.
Unfortunately this isn't perfect either, because it seems the RIS
detection sometimes just isn't run, which means that the icon never
changes and the test times out. Maybe @simonster has an idea why that's
happening.