This reverts commit 77838343.

Reason for revert: Mysterious win32 test262 failures: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32%20-%20debug/30119/overview

Original change's description:
> [wasm-simd] Remove add horiz instructions
>
> Bug: v8:6020
> Change-Id: I0605798d03f2e9f9c3c07c49141289889a10a3b0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2727204
> Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
> Commit-Queue: Zhi An Ng <zhin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73180}

Bug: v8:6020
Change-Id: Id1a58d7689d506b17ed04a7df67fec4003bc523d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2733662
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#73181}