run tests in miri

[hawkw]

it's probably a bad idea to try to run the loom tests in miri, since they are quite long & running code in miri is significantly slower than running actual compiled code. but, then, we would need a good way to ensure that at least the likeliest concurrent permutations are exercised in miri...

[hawkw]

oh, looks like miri doesn't play nice with thread-locals (unsurprising), which means that both loom and the crate itself won't compile. that tracks.

since miri doesn't support concurrency, though, running loom tests in miri is theoretically a good idea, since loom's simulated concurrency would allow testing "concurrent" code in miri...