This reverts commit b6fb2707.

Reason for revert: TSan issues, e.g. https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20TSAN/26177

Original change's description:
> [wasm][gc] Free WasmCode objects
> 
> This adds the next step to freeing code: We free the actual C++
> {WasmCode} objects. This will cause UAF if any C++ code uses stale
> references.
> The underlying machine code will still not be freed.
> 
> For simplicity, this CL changes the vector of owned_code to an ordered
> set, such that lookup and removal is much simpler. The drawback is that
> insertion is now more expensive.
> 
> R=​mstarzinger@chromium.org
> 
> Bug: v8:8217
> Change-Id: I07fc81167816637fbaad6c06ff79e3f952f2fde8
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1593080
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#61165}

TBR=mstarzinger@chromium.org,clemensh@chromium.org

Change-Id: I167a8d806a8c6ac1c90e0743cdf86d492389bbed
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:8217, v8:9200
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1593305Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61176}