Update the stdarch submodule

alexcrichton · alexcrichton · commit bcfdf55efe67 · 2021-08-24T09:02:44.000-07:00
This notably brings in a number of codegen updates to ensure that wasm
simd intrinsics generate the expected instruction with LLVM 13
diff --git a/library/stdarch b/library/stdarch
@@ -1 +1 @@
-Subproject commit c158cfd38e20d855f5d6ca8a5a101eefb82604a8
+Subproject commit 89b0e355bc3cff5cddec2290c84f36eb3a026aad
