Fix the racy test. (#1753)
Fix the racy test. (#1753)

The problem is that the original test presumed the 2 other backgound calls have
finished already.
Which is not really true always.
E.g. here: https://github.com/knative/pkg/pull/1746/checks?check_run_id=1179720602

Also other nits around the file
knative/pkg,knative/pkg