Add the ability to use params arguments properly when using a parametrised test fixture

[Shiney]

Added some tests for this and made the methods that call the constructors on TestFixtures able to allow params arguments. This doesn't really address the duplication with similar code for calling test methods but that didn't seem particularly quick to also fix as part of this.

Fixes #1459

[manfred-brands]

Thanks @Shiney for your contribution.
I only have a few small comments.

[Shiney]

Hi @manfred-brands I tried to do your comments about swapping the order of the checks but it didn't seem to end up making the code much nicer in my opinion because it ended up having to do all sorts of extra special code to deal with the case where zero parameters provided were used for the params argument

[manfred-brands]

@Shiney I tried to push my review changes, but you didn't allow maintainers to update the fork.
Could you please address the other outstanding issues.

[Shiney]

Yes will do this soon

[Shiney]

I believe I've fixed all the comments and have ticked the Allow edits by maintainers button just in case

[manfred-brands]

Thanks @Shiney. I have fixed some spacing issues as earlier this week we enabled enforcing these rules.

[manfred-brands]

Nothing further.