Implement tests for atomic memory orders

[t4c1]

Existing tests are fundamentally broken and are being removed in #783. New tests need to be designed and implemented.

[t4c1]

I looked into these tests, however no test I wrote actually failed when using wrong memory order (a test would only fail if compiler of device reordered instructions around the atomic). @steffenlarsen is there even interest in having such tests in the test suite?

[steffenlarsen]

I think they would be nice to have. Say we have a bug in the reordering it would be much easier to identify it in a small test rather than in production code. I don't think we need to test for all types though, so simple minimal tests would probably be good enough.