Rollup merge of #123833 - dpaoliello:stdarch, r=Amanieu

Update stdarch submodule

`asm_experimental_arch` is required in `core` as we're now using unstable inline assembly when building Arm64EC.

Brings in the fix for <https://github.com/rust-lang/stdarch/issues/1555> (cc `@tslnc04).`

r? `@Amanieu`

library/core/src/lib.rs

@@ -111,6 +111,7 @@
 // tidy-alphabetical-start
 #![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(array_ptr_get)]
+#![feature(asm_experimental_arch)]
 #![feature(char_indices_offset)]
 #![feature(const_align_of_val)]
 #![feature(const_align_of_val_raw)]

library/stdarch

@@ -1 +1 @@
-Subproject commit 967e7afd87cbea3232581a4a55031134ab88f595
+Subproject commit 7df81ba8c3e2d02c2ace0c5a6f4f32d800c09e56