Rollup merge of #102232 - Urgau:stabilize-bench_black_box, r=TaKO8Ki

Stabilize bench_black_box

This PR stabilize `feature(bench_black_box)`.

```rust
pub fn black_box<T>(dummy: T) -> T;
```

The FCP was completed in https://github.com/rust-lang/rust/issues/64102.

`@rustbot` label +T-libs-api -T-libs

src/test/incremental/spans_significant_w_panic.rs

@@ -8,7 +8,6 @@
 // compile-flags: -C overflow-checks=on -Z query-dep-graph
 
 #![feature(rustc_attrs)]
-#![feature(bench_black_box)]
 #![rustc_partition_codegened(module = "spans_significant_w_panic", cfg = "rpass2")]
 #![rustc_partition_codegened(module = "spans_significant_w_panic", cfg = "rpass4")]
 

src/test/ui/box/issue-95036.rs

@@ -1,7 +1,7 @@
 // compile-flags: -O
 // build-pass
 
-#![feature(allocator_api, bench_black_box)]
+#![feature(allocator_api)]
 
 #[inline(never)]
 pub fn by_ref(node: &mut Box<[u8; 1], &std::alloc::Global>) {

src/test/ui/consts/cast-discriminant-zst-enum.rs

@@ -1,6 +1,5 @@
 // run-pass
 // Test a ZST enum whose dicriminant is ~0i128. This caused an ICE when casting to an i32.
-#![feature(bench_black_box)]
 use std::hint::black_box;
 
 #[derive(Copy, Clone)]

src/test/ui/consts/const_discriminant.rs

@@ -1,6 +1,5 @@
 // run-pass
 #![feature(const_discriminant)]
-#![feature(bench_black_box)]
 #![allow(dead_code)]
 
 use std::mem::{discriminant, Discriminant};

src/test/ui/issues/issue-99838.rs

@@ -1,5 +1,5 @@
 // run-pass
-#![feature(bench_black_box)]
+
 use std::hint;
 
 struct U16(u16);

src/test/ui/oom_unwind.rs

@@ -4,8 +4,6 @@
 // needs-unwind
 // only-linux
 
-#![feature(bench_black_box)]
-
 use std::hint::black_box;
 use std::mem::forget;
 use std::panic::catch_unwind;

src/test/ui/process/process-panic-after-fork.rs

@@ -7,7 +7,6 @@
 // ignore-sgx no processes
 // ignore-android: FIXME(#85261)
 
-#![feature(bench_black_box)]
 #![feature(rustc_private)]
 #![feature(never_type)]
 #![feature(panic_always_abort)]

src/test/ui/sanitize/address.rs

@@ -5,9 +5,7 @@
 //
 // run-fail
 // error-pattern: AddressSanitizer: stack-buffer-overflow
-// error-pattern: 'xs' (line 15) <== Memory access at offset
-
-#![feature(bench_black_box)]
+// error-pattern: 'xs' (line 13) <== Memory access at offset
 
 use std::hint::black_box;
 

src/test/ui/sanitize/hwaddress.rs

@@ -10,8 +10,6 @@
 // run-fail
 // error-pattern: HWAddressSanitizer: tag-mismatch
 
-#![feature(bench_black_box)]
-
 use std::hint::black_box;
 
 fn main() {

src/test/ui/sanitize/leak.rs

@@ -6,8 +6,6 @@
 // run-fail
 // error-pattern: LeakSanitizer: detected memory leaks
 
-#![feature(bench_black_box)]
-
 use std::hint::black_box;
 use std::mem;
 

src/test/ui/sanitize/memory-eager.rs

@@ -17,7 +17,6 @@
 
 #![feature(core_intrinsics)]
 #![feature(start)]
-#![feature(bench_black_box)]
 
 use std::hint::black_box;
 use std::mem::MaybeUninit;

src/test/ui/sanitize/memory.rs

@@ -16,7 +16,6 @@
 
 #![feature(core_intrinsics)]
 #![feature(start)]
-#![feature(bench_black_box)]
 #![allow(invalid_value)]
 
 use std::hint::black_box;