alloc: #[allow(instantly_dangling_pointer)] for a test about dangling pointers

Author: GrigorenkoPV

library/alloc/tests/boxed.rs

@@ -4,6 +4,7 @@ use core::mem::MaybeUninit;
 use core::ptr::NonNull;
 
 #[test]
+#[allow(instantly_dangling_pointer)]
 fn uninitialized_zero_size_box() {
     assert_eq!(
         &*Box::<()>::new_uninit() as *const _,