Revert of [turbofan] Improve codegen for 8- and 16-bit memory comparisons on Intel platforms (patchset #3 id:40001 of https://codereview.chromium.org/2605863002/ )

Reason for revert:
Breaks wasm benchmark (http://crbug.com/v8/5798).

Original issue's description:
> [turbofan] Improve codegen for 8- and 16-bit memory comparisons on Intel platforms
>
> Recognize and emit in-memory comparisons of 8-bit and 16-bit values with
> immediate values that fit.
>
> LOG=N
> R=epertoso@chromium.org
>
> Review-Url: https://codereview.chromium.org/2605863002
> Cr-Commit-Position: refs/heads/master@{#41971}
> Committed: https://chromium.googlesource.com/v8/v8/+/be11812c53ff6c8ce320887bc76a3b60d8103695

TBR=danno@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.

Review-Url: https://codereview.chromium.org/2618443003
Cr-Commit-Position: refs/heads/master@{#42092}