Rollup merge of #108419 - tgross35:atomic-as-ptr, r=m-ou-se

Stabilize `atomic_as_ptr`

Fixes #66893

This stabilizes the `as_ptr` methods for atomics. The stabilization feature gate used here is `atomic_as_ptr` which supersedes `atomic_mut_ptr` to match the change in https://github.com/rust-lang/rust/pull/107736.

This needs FCP.

New stable API:

```rust
impl AtomicBool {
    pub const fn as_ptr(&self) -> *mut bool;
}

impl AtomicI32 {
    pub const fn as_ptr(&self) -> *mut i32;
}

// Includes all other atomic types

impl<T> AtomicPtr<T> {
    pub const fn as_ptr(&self) -> *mut *mut T;
}
```

r? libs-api
``@rustbot`` label +needs-fcp

1 files changed, 0 insertions, 1 deletions

diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 7837dd276d2..4e7b6080835 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -274,7 +274,6 @@
 #![feature(utf8_chunks)]
 //
 // Library features (core):
-#![feature(atomic_mut_ptr)]
 #![feature(char_internals)]
 #![feature(core_intrinsics)]
 #![feature(duration_constants)]