- Cache process-id as process-static variable
- Only extract the script name once per SFI

Change-Id: I4549c2a3849d57dbcfa115401719e22422cfac6a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3477113Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79206}