This is a reland of 1025bf26

Changes since revert:

- TSAN issue fixed by https://crrev.com/c/3475084
- Skip the shared-struct-workers test until shared GC deadlock is fixed,
  being tracked in v8:12645

Original change's description:
> [shared-struct] Prototype JS shared structs
>
> Unlike the Stage 1 proposal, for simplicity the prototype does not add
> any new syntax, instead opting for exposing a SharedStructType
> constructor which takes an array of field names. This type constructor
> returns constructors for shared structs.
>
> Shared structs can be shared across Isolates, are fixed layout, have no
> prototype, have no .constructor, and can only store primitives and
> other shared structs.
>
> The initial prototype does not have TurboFan support.
>
> Bug: v8:12547
> Change-Id: I23bdd819940b42139692bcdb53d372099b0d4426
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3390643
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Marja Hölttä <marja@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#79156}

Bug: v8:12547
Change-Id: Ic1f5cf9fa9791ae2d5d5dc7c110614ca10b5d98e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3475078Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79215}