Not sure why I originally chose to name it LoadMem32Zero instead of
Load32Zero like the proposal. This fixes it.

Bug: v8:10713
Change-Id: If05603f743213bc6b7aea0ce22c80ae4b3023ccf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2481824Reviewed-by: Bill Budge <bbudge@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70630}