Auto merge of #53604 - oli-obk:min_const_fn, r=Centril,varkor

Auto merge of #53604 - oli-obk:min_const_fn, r=Centril,varkor

Implement the `min_const_fn` feature gate

cc @RalfJung @eddyb

r? @Centril

implements the feature gate for #53555

I added a hack so the `const_fn` feature gate also enables the `min_const_fn` feature gate. This ensures that nightly users of `const_fn` don't have to touch their code at all.

The `min_const_fn` checks are run first, and if they succeeded, the `const_fn` checks are run additionally to ensure we didn't miss anything.