This reverts commit dc369749.

Reason for revert: nosse variant failures: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux%20-%20debug/33279/overview

Original change's description:
> [wasm-gc] Liftoff support part 4: subtyping
>
> This adds support for the following instructions:
> struct.new_default, rtt.sub, ref.test, ref.cast
>
> Bug: v8:7748
> Change-Id: I7423ddd7a83c80cb1e82c620780c27bec59ec762
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2593341
> Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#71805}

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

Change-Id: I06bb493852223aecf221c9149bc7b034b1fb13ad
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7748
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2596497Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71806}