This fixes an msan compile error after https://crrev.com/c/1587381.

TBR=jkummerow@chromium.org

No-Try: true
No-Tree-Checks: true
Bug: v8:9183
Change-Id: I50c5fc2ddb698a6441896ec393bce62eee7afdc9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1587390Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61082}