This reverts commit a3ce2f6d.

Reason for revert: speculative revert due to waterfall unhappiness (looks like bot weirdness though?)

Original change's description:
> [wasm-gc] Liftoff support part 5: i31
>
> This implements support for i31.get_s and i31.get_u.
>
> Bug: v8:7748
> Change-Id: Icbfddbc2ff46b4eb6bf3edf7b3a794f9797361d4
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2595309
> Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#71808}

TBR=jkummerow@chromium.org,clemensb@chromium.org

Change-Id: I5050f16fdaf355d178935f523a9bec516302d2a1
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7748
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2596337Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71810}