Rollup merge of #70769 - RalfJung:fixed, r=Dylan-DPC
Rollup merge of #70769 - RalfJung:fixed, r=Dylan-DPC

Miri: remove an outdated FIXME

We even [have a test ](https://github.com/rust-lang/rust/blob/49dc2f9f091748beb1a8a9d5b3eb3bbe7362c3bd/src/test/ui/consts/miri_unleashed/drop.rs) making sure that we detect dropping with a non-const implementation.

r? @oli-obk

aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust