.. in preparation for integrating addtl tiers into a single tiering
system.

1. Explicitly spell out whether the request is concurrent or not.
2. Explicitly request the target compiler.

Bug: v8:7700
Change-Id: I9d6e9f6a5d5f0f7218fe136ff50cea2ad7987f67
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3460739
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79092}