This reverts commit cfe9544a.

Reason for revert: Some spec tests fail:
https://ci.chromium.org/p/v8/builders/ci/V8%20Arm%20-%20debug/15933

Original change's description:
> [wasm-simd][scalar-lowering] Enable some spec tests
> 
> These tests can now be enabled as we implemented more scalar lowering
> support.
> 
> Bug: v8:10507
> Change-Id: Ida5f896300e074db079ec24720302729b0582d9d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2411774
> Reviewed-by: Bill Budge <bbudge@chromium.org>
> Commit-Queue: Zhi An Ng <zhin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70006}

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

Change-Id: Idb2da40178860f045ffab9ab5b2c8b1f2ebafcf6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10507
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2419036Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70010}