This is a reland of b6fb2707.

Unchanged reland, TSan issue were fixed in https://crrev.com/c/1593340
and https://crrev.com/c/1594553.

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

Bug: v8:8217
Change-Id: I809832bb609663d794c7aafcf071823db7fb6212
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1594436
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61215}