The test relies on certain maps not dying but didn't ensure that.

Bug: v8:10783
Change-Id: I708f7fc027ee0bf5656be9bb4f29130f5b924597
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2340912Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Auto-Submit: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69282}