Work around SUREFIRE-1679 junit-platform-launcher dependency issue

[philwebb]

Triggered by #17491 we've discovered that surefire has a bug which means we cannot directly depend on junit-platform-launcher. Until it's fixed, we'll need to use reflection.

[wilkinsona]

I've raised SUREFIRE-1679.

[dreis2211]

You are awesome

[dreis2211]

@wilkinsona Could be that this is already fixed via SUREFIRE-1585.

[wilkinsona]

I'm not sure. I've tested with both 3.0.0-M3 and 3.0.0-SNAPSHOT and the problem still occurs. Unfortunately, 3.0.0-SNAPSHOT resolves to 3.0.0-20190214.112538 so I'm missing out on 5 months of changes. The code that I believe is problematic is still there in master so my suspicion is that the problem still exists.