This method is only called from {AllocateWasmMemory}, so does not need
to be public.

R=jkummerow@chromium.org

Bug: v8:10949
Change-Id: Idf411179b6cf816adc111ceebf79335177e3440b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3789502Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82019}