This reverts commit 04ce88ea.

Reason for revert: TSAN failure: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20TSAN/32135

Original change's description:
> [wasm-gc] Implement rtt.sub
> 
> RTTs are internally represented as Maps. To store supertype information,
> this patch introduces a WasmTypeInfo object, which is installed on Wasm
> objects' Maps and points at both the off-heap type information and the
> parent RTT.
> In this patch, rtt.sub always creates a fresh RTT. The canonicalization
> that the proposal requires will be implemented later.
> 
> Bug: v8:7748
> Change-Id: I8286dd11f520966155cd95c2bd844ec34fccd131
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2260566
> Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#68564}

TBR=ulan@chromium.org,jkummerow@chromium.org,tebbi@chromium.org

Change-Id: I311732e1ced4de7a58b87d4a9b6056e0d62aa986
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7748
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2270734Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68567}