Drive-by-fix:
- Wait for linux-perf to flush large profile files

No-try: True
Change-Id: I729aa897e3f55fc92a9412208322ee099029453f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3605282Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80154}