This refactors the FastApiCall reduction to be more explicit about
which inputs of the JSCall node are used.

Bug: v8:8888
Change-Id: Ia950bbfcf359ec4ae232b8dd21adafb0b4a05177
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2276032
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68628}