"--emit mir" does not emit drop shim

[RalfJung]

When compiling code that generates drop shims, such as

struct Bar(u16); // ZSTs are tested separately

static mut DROP_COUNT: usize = 0;

impl Drop for Bar {
    fn drop(&mut self) {
        assert_eq!(self.0 as usize, unsafe { DROP_COUNT }); // tests whether we are called at a valid address
        unsafe { DROP_COUNT += 1; }
    }
}

fn main() {
    let b = [Bar(0), Bar(1), Bar(2), Bar(3)];
    assert_eq!(unsafe { DROP_COUNT }, 0);
    drop(b);
    assert_eq!(unsafe { DROP_COUNT }, 4);

    // check empty case
    let b : [Bar; 0] = [];
    drop(b);
    assert_eq!(unsafe { DROP_COUNT }, 4);
}

I would expect the file created by rustc --emit mir to also contain the drop shim. However, that is not the case.

This is related to #53532 but not identical: the code for selecting what gets dumped with -Zdump-mir and --emit=mir is, from all I can see, entirely independent. Just the actual printing is shared.