msvc != x86

It's possible to get here while building for ARM64.

Change-Id: Icf621059f4cfdec28d71437917ebb348369e6c26
Reviewed-on: https://chromium-review.googlesource.com/c/1368105


Reviewed-by: Leon Scroggins <scroggo@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#614819}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 6ffae24943b91fd5ad63a5a6bec18c544244877b