This implements the last bits of basic concurrent Maglev compilation.
When jobs have been processed, schedule an interrupt to trigger codegen
and building the Code object on the main thread.

Bug: v8:7700
Change-Id: I348ade4777ddddf7c3a6b0575d9f51e5fa00c9fb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3528494Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79516}