Using shm_open with a constant name can lead to race conditions with
other V8 instances using (and unlinking) the same shared memory object.

Bug: v8:12636
Change-Id: Ic2d2317f99c1df7aedec2dc52b187c64eea11d2c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3468899Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Samuel Groß <saelo@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79146}