This adds an abstraction for command-line arguments for each of the
two comparison runs done in correctness fuzzing. No functional
changes intended.

No-Try: true
Bug: chromium:1023091
Change-Id: I9421715c4904416b9aaf53848954a5248c79ffd9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1906372
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64979}