New tracking issues for const_ops and const_cmp
Let's do a clean start with new tracking issues to avoid mixing things up with the previous constification.
I assume the fact that the `PartialEq` *trait* and *impls* used different feature names was a mistake (the feature name on the impl is entirely irrelevant anyway).
Part of https://github.com/rust-lang/rust/issues/143800, https://github.com/rust-lang/rust/issues/143802
r? ``@oli-obk``