The first operand of the select op isn't restricted to any particular
replacement SimdType, since we can convert any type to Int32x4.

Change-Id: I1821b2ebdc1a192518a2ecc0cb13951a98bb3337
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2534211Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71167}