* feat(oonimkall): instrument code to understand CI issue
It seems ~difficult to reproduce the problem locally and I could not
see it after five runs of
```
go test -race -count 1 ./pkg/oonimkall/...
```
So, here's some diagnostic code that could help understanding the
reference issue https://github.com/ooni/probe/issues/1785.
Also, it seems the issue pops up much more frequently when running
CI anyway. So, I am going to leave this diff around and when it
appears again I have more context to fix the issue.
* fix(oonimkall): skip flaky test in short mode
See https://github.com/ooni/probe/issues/1785