Rollup merge of #57273 - alexcrichton:update-stdsimd, r=nikomatsakis

Update the stdsimd submodule Add a new cmpxchg16b intrinsics for x86_64 and some corrections for ARM/AArch64

Author: kennytm

src/libcore/lib.rs

@@ -110,6 +110,7 @@
 #![feature(aarch64_target_feature)]
 #![feature(wasm_target_feature)]
 #![feature(avx512_target_feature)]
+#![cfg_attr(not(stage0), feature(cmpxchg16b_target_feature))]
 #![feature(const_slice_len)]
 #![feature(const_str_as_bytes)]
 #![feature(const_str_len)]