Auto merge of #91354 - fee1-dead:const_env, r=spastorino

Cleanup: Eliminate ConstnessAnd

This is almost a behaviour-free change and purely a refactoring. "almost" because we appear to be using the wrong ParamEnv somewhere already, and this is now exposed by failing a test using the unstable `~const` feature.

We most definitely need to review all `without_const` and at some point should probably get rid of many of them by using `TraitPredicate` instead of `TraitRef`.

This is a continuation of https://github.com/rust-lang/rust/pull/90274.

r? `@oli-obk`

cc `@spastorino` `@ecstatic-morse`

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -918,6 +918,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         } else {
             self.param_env
         };
+        let param_env = param_env.with_const();
         let val = self.tcx.eval_to_allocation_raw(param_env.and(gid))?;
         self.raw_const_to_mplace(val)
     }