This test fails in --stress-opt mode because backing stores of
memories/arraybuffers that are postMessage()'d leak in d8. In normal
mode, only ~16 memories are allocated, which is not enough to OOM,
but in stress mode, it can be 5x that number. Should be fixed
by upcoming ownership changes.

BUG=v8:9380
R=clemensh@chromium.org

Change-Id: Iecec07d15339cf43b23f128f13d570dfe3b32130
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1708475Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62802}