We splat two different values and then shuffle them together so that we
can test pairwise addition of two different values.

Bug: v8:11086
Change-Id: Id3bb34e9bfe21b6c5cb1d7eee3745c6c9e262f24
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2776513Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73590}