Rollup merge of #130568 - eduardosm:const-float-methods, r=RalfJung,tgross35

Make some float methods unstable `const fn`

Some float methods are now `const fn` under the `const_float_methods` feature gate.

I also made some unstable methods `const fn`, keeping their constness under their respective feature gate.

In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval (cc `@RalfJung).`

Tracking issue: https://github.com/rust-lang/rust/issues/130843

```rust
impl <float> {
    // #[feature(const_float_methods)]
    pub const fn recip(self) -> Self;
    pub const fn to_degrees(self) -> Self;
    pub const fn to_radians(self) -> Self;
    pub const fn max(self, other: Self) -> Self;
    pub const fn min(self, other: Self) -> Self;
    pub const fn clamp(self, min: Self, max: Self) -> Self;
    pub const fn abs(self) -> Self;
    pub const fn signum(self) -> Self;
    pub const fn copysign(self, sign: Self) -> Self;

    // #[feature(float_minimum_maximum)]
    pub const fn maximum(self, other: Self) -> Self;
    pub const fn minimum(self, other: Self) -> Self;

    // Only f16/f128 (f32/f64 already const)
    pub const fn is_sign_positive(self) -> bool;
    pub const fn is_sign_negative(self) -> bool;
    pub const fn next_up(self) -> Self;
    pub const fn next_down(self) -> Self;
}
```

r? libs-api

try-job: dist-s390x-linux

library/std/src/lib.rs

@@ -289,6 +289,7 @@
 #![feature(cfg_target_thread_local)]
 #![feature(cfi_encoding)]
 #![feature(concat_idents)]
+#![feature(const_float_methods)]
 #![feature(decl_macro)]
 #![feature(deprecated_suggestion)]
 #![feature(doc_cfg)]