Make QC's reproduceMsg optional

[larsrh]

I suggest the addition of a new option to disable the message Use --quickcheck-replay ... when a QC property fails unexpectedly.

https://github.com/feuerbach/tasty/blob/257675f273bd87d58c129372167ae14ddca68a86/quickcheck/Test/Tasty/QuickCheck.hs#L124-L128

The reason is that we're using tasty without the built-in command-line parsing (setting every option manually), producing an HTML file which is presented to our students. There's no way for them to modify the test invocation, which makes that message a little bit confusing.

I can work on a PR if you'd be okay with the change.

[UnkindPartition]

Ok, go ahead.