Enable Miri testing

Consider automating [Miri](https://github.com/rust-lang/miri#miri) test runs - the undefined behavior detector tool - to run in CI.

```bash
rustup component add --toolchain nightly-x86_64-unknown-linux-gnu miri
cargo +nightly miri test
```

Note that at the moment at least one of the tests fails, but I am not certain if this is the fault of the test itself.

Start by running the provided rustup command and `cargo +nightly miri test` to identify the failing test. Then locate the repository's CI configuration and determine how to add the Miri run; the work is done when Miri runs in CI and the existing failure is explained or resolved.

Written by the indexing model from the issue text.