When lowering signatures, we must preserve the separation of parameters
into tagged and untagged sections.

Fixed: chromium:1320614
Change-Id: I8119ba23e35f499630c2d2494e99191ca793cb1a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3620283Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80327}