Auto merge of #129261 - tgross35:rollup-xjbvqx7, r=tgross35

Rollup of 7 pull requests

Successful merges:

 - #127679 (Stabilize `raw_ref_op` (RFC 2582))
 - #128084 (Suggest adding Result return type for associated method in E0277.)
 - #128628 (When deduplicating unreachable blocks, erase the source information.)
 - #128902 (doc: std::env::var: Returns None for names with '=' or NUL byte)
 - #129048 (Update `crosstool-ng` for loongarch64)
 - #129116 (Include a copy of `compiler-rt` source in the `download-ci-llvm` tarball)
 - #129208 (Fix order of normalization and recursion in const folding.)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

tests/fail/dangling_pointers/dangling_pointer_to_raw_pointer.rs

@@ -1,4 +1,3 @@
-#![feature(raw_ref_op)]
 #![feature(strict_provenance)]
 use std::ptr;
 

tests/fail/function_calls/return_pointer_aliasing_read.rs

@@ -1,7 +1,6 @@
 //@revisions: stack tree none
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@[none]compile-flags: -Zmiri-disable-stacked-borrows
-#![feature(raw_ref_op)]
 #![feature(core_intrinsics)]
 #![feature(custom_mir)]
 

tests/fail/function_calls/return_pointer_aliasing_write.rs

@@ -1,7 +1,6 @@
 // This does need an aliasing model and protectors.
 //@revisions: stack tree
 //@[tree]compile-flags: -Zmiri-tree-borrows
-#![feature(raw_ref_op)]
 #![feature(core_intrinsics)]
 #![feature(custom_mir)]
 

tests/fail/function_calls/return_pointer_aliasing_write_tail_call.rs

@@ -1,7 +1,6 @@
 // This does need an aliasing model and protectors.
 //@revisions: stack tree
 //@[tree]compile-flags: -Zmiri-tree-borrows
-#![feature(raw_ref_op)]
 #![feature(core_intrinsics)]
 #![feature(custom_mir)]
 #![feature(explicit_tail_calls)]

tests/fail/function_calls/return_pointer_on_unwind.rs

@@ -1,6 +1,5 @@
 // Doesn't need an aliasing model.
 //@compile-flags: -Zmiri-disable-stacked-borrows
-#![feature(raw_ref_op)]
 #![feature(core_intrinsics)]
 #![feature(custom_mir)]
 

tests/pass/function_calls/return_place_on_heap.rs

@@ -1,4 +1,3 @@
-#![feature(raw_ref_op)]
 #![feature(core_intrinsics)]
 #![feature(custom_mir)]