Allow specifying a default `trials` value

[DavidDTA]

It would be nice to be able to specify a default trials value for an entire test run. The idea would be to do a more rigorous run once per night to try to catch more issues while still keeping normal test runs fast.

[GAJaloyan]

Hi, bumping up this issue: I had a similar issue with parameterizing JQF, and it seems that the trials value is controlled by quickcheck. Is there an easy way of doing this (compared to my current macro expansion)?
rohanpadhye/JQF#249
Thanks. George.