161: Fix JUnit 5 and Surefire issues.

[michael-simons]

Surefire from version 2.22.0 brings its own JUnit 5 platform provider.
The previous setup was incomplete and missed the engine as dependency of
surefire.

Your test coverage was zero as no test has been run.

The fix was easy: Just use at least surefire 2.22.1 (will work on JDK
11, too) and remove all the manual declaration of JUnit 5 platform,
launcher and runner.

In addition I'd recommend here to get rid of JUnit 4 as well, so nobody
adds an old JUnit 4 test by coincidence.

Also bump JUnit to the most recent version.

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This change is 

[teobais]

Many thanks for this one, @michael-simons !

To begin with, a bit of background: the reason of keeping the junit-4-compatible-dependencies was to have a smooth migration to JUnit5 (end goal was to indeed get rid of them as well as the junit4 dependency - previously all of our tests were written in junit4).

On topic, what you mentioned sounds pretty cool (and I'll conduct some research while it builds). Unfortunately, though, I cannot test it locally, since I'm on a Mac and the issue only appeared on windows.

@keilw could you check this locally as well (irrespectively of Codacy's outcome)?

[michael-simons]

I've added one more commit. I think it's better to specify the surefire plugin not in a profile but on main level. Otherwise tests will only run in base-jar profile.

[michael-simons]

Builds with JDK 11 on Windows 7, actually without the changes as well.

I would guess that due to the fact that in the default profile no version of surefire is specified, Maven takes the latest one in it's default repo and that is by chance one on @keilw machine that doesn't include a version compatible with JUnit 5.