Auto merge of #110393 - fee1-dead-contrib:rm-const-traits, r=oli-obk

Rm const traits in libcore

See [zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/146212-t-compiler.2Fconst-eval/topic/.60const.20Trait.60.20removal.20or.20rework)

* [x] Bless ui tests
* [ ] Re constify some unstable functions with workarounds if they are needed

Author: bors