Moves XCTestCase.validate into its own module

[kristofferjohansson]

Resolves #62 by moving the validate extension on XCTestCase to its own module.

[phausler]

Overall this looks great, I presume that it works fine for importing to other project testing on both Darwin and Linux?

[phausler]

so this prevents us from doing release-mode testing of perf. I am of the belief that this DEFINITELY should be tested, but we kinda need to settle on a way to do this AND accommodate for testing performance too

[kristofferjohansson]

I actually didn't realize that this prevents that. I thought about moving the tests to their own test target for the new module, but they depend on other types in the AsyncAlgorithmsTests module and I tried to make as few changes as possible. I guess making more of the methods in the extension doesn't feel like a good solution either?

[phausler]

I presume this is needed for the clock tests eh?

[kristofferjohansson]

This must have been a miss on my part, I have pushed a commit that removes this.

[kristofferjohansson]

Overall this looks great, I presume that it works fine for importing to other project testing on both Darwin and Linux?

Thanks! I have only tested importing it to a test target in another package on Darwin so far. I can see if I'm able to test it on Linux as well.

[phausler]

was able to test this out on linux, seems like it works just fine!