This reverts commit de88bfb2.

Reason for revert: Breaks msvc build https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Win64%20-%20msvc/5765

Original change's description:
> [wasm-simd] Implement remaining I8x16 SIMD ops on x64
> 
>  - Implementation for I8x16 Shifts, and Mul
>  - Fix convert bug
>  - Enable all tests except for shuffle tests
> 
> Change-Id: Id1a469d2883c30ea782c51d21dc462d211f94420
> Reviewed-on: https://chromium-review.googlesource.com/c/1318609
> Reviewed-by: Bill Budge <bbudge@chromium.org>
> Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#57254}

TBR=bbudge@chromium.org,gdeepti@chromium.org

Change-Id: I09efd8002e27f457e89250336e6c3a12d8d9682c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/1318097Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57257}