=pro #15178 enable junit tests in akka-streams again

The junit-interface is treating "anything it cannot understand" as a
globbing pattern, thus when it didn't understand ScalaTest options, it
used them for globbing, and of course none of our junit tests matched
the "-oDF" pattern for example.

Debugged this with Stefan and we've opened an issue to improve the
integration in this respect:
https://github.com/sbt/junit-interface/issues/60

Resolves #15178
Merge pull request #16053 from ktoso/wip-junit-tests-not-running-ktoso

=pro #15178 enable junit tests in akka-streams again