aggregateCSVReportsTwo should create two aggregate reports

[TGiles]

Describe the bug
There's an intermittent bug (that I can't reproduce locally) that involves aggregateCSVReportsTwo should create two aggregate reports.

To Reproduce
I wish I knew how to consistently reproduce. I have no idea why this is happening.

Expected behavior
The test should consistently pass (or consistently fail if new code breaks the existing behavior).

Additional context
If anyone else is able to reproduce this consistently, I'd be very grateful. I can't reproduce on my Windows box or Linux VM, only seems to happen on the CI servers.

[TGiles]

The failure rate seems to have gone down with the changes introduced in 57c916a but I'm going to keep this open for a bit longer to make sure.

[L00Cyph3r]

What is the exact error you are getting? As far as I can see the only thing that could mean something is that _readReportDirectory() does a console.error which might trigger something. If you have an error or a link to a failed CI-job I can try to poke around a bit more