rustup
This test was removed in rustc in https://github.com/rust-lang/rust/pull/87141.
We added it in https://github.com/rust-lang/miri/pull/1430, and possibly that "interesting case in unsizing" is not covered by tests now -- but I don't remember what that case is.^^ If/when `impl Trait` in bindings comes back, we should copy the new rustc tests to Miri as well.