Rollup merge of rust-lang#55291 - kazcw:master, r=nikomatsakis

kennytm · kennytm · commit 163ffa09c76e · 2018-10-25T15:30:58.000+08:00
Update stdsimd submodule Fixes a SSE2 bug. (rust-lang#55249)
diff --git a/src/stdsimd b/src/stdsimd
@@ -1 +1 @@
-Subproject commit 307650500de5b44dc1047dc9d15e449e09d92b57
+Subproject commit 431766a3fbcfb6dafb2d5a3866c1609bf44ee554
