Run tests via miri for compiler crates that use `unsafe`

[WaffleLapkin]

#109971 made it so compiler/rustc_data_structures pass tests under miri. We should add testing under miri to CI in order to prevent future unsound bugs that can be detected with it.

Running the whole compiler through miri seems impossible, but running tests of crates that use unsafe code (like rustc_data_structures) seems both plausible and useful.

[RalfJung]

If we do this for the compiler tests we should definitely also do it for std tests, shouldn't we?

That currently happens externally via https://github.com/rust-lang/miri-test-libstd. But I wouldn't mind catching these things before they land.