Rollup merge of #135347 - samueltardieu:push-qvyxtxsqyxyr, r=jhpratt

Use `NonNull::without_provenance` within the standard library

This API removes the need for several `unsafe` blocks, and leads to clearer code. It uses feature `nonnull_provenance` (#135243).

Close #135343

library/std/src/lib.rs

@@ -342,6 +342,7 @@
 #![feature(lazy_get)]
 #![feature(maybe_uninit_slice)]
 #![feature(maybe_uninit_write_slice)]
+#![feature(nonnull_provenance)]
 #![feature(panic_can_unwind)]
 #![feature(panic_internals)]
 #![feature(pin_coerce_unsized_trait)]