This removes a loop that runs exactly one or two times by straight-line
code for the two cases. This should make it more readable and easier to
maintain.

R=thibaudm@chromium.org

Bug: v8:10576
Change-Id: I242bc4a7f7333b04ec39e79dc530625fb5e2305f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2287505Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68800}