Rollup merge of #56682 - alexcrichton:update-stdsimd, r=nikomatsakis

Update the stdsimd submodule

Includes some new stabilized intrinsics for the wasm32 target!

Closes #56292
diff --git a/src/stdsimd b/src/stdsimd
index 5e628c5..3c0503d 160000
--- a/src/stdsimd
+++ b/src/stdsimd
@@ -1 +1 @@
-Subproject commit 5e628c5120c619a22799187371f057ec41e06f87
+Subproject commit 3c0503db8439928e42c1175f0009c506fc874ae9