In https://crrev.com/c/3522896 we changed the last_id_ to be a member
variable. This subtly changed how profile id's were generated.

This CL changes this part back to a static variable that guarantees
process-wide unique profile ids.

Bug: chromium:1330726, chromium:1297283
Change-Id: I5f3dddcbbc156d0dee7d1eedde8a731c53d080dc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3684289
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80902}