Initial implementation for concurrent shared arrays. Current implementation exposes a `SharedArray` constructor, but its syntax might
change in the future.
Shared arrays can be shared across Isolates, have a fixed size, have no
prototype, have no constructor, and can only store primitives, shared structs and other shared arrays. With this CL shared structs are also allowed to store shared arrays.
The Backing storage for the SharedArrays is a `FixedArrayBase`. This CL introdces a new ElementKind: `SHARED_ARRAY_ELEMENTS`. The new kind should match the overall functionality of the `PACKED_SEALED_ELEMENTS` kind, but having it as standalone kind allows for easier branching in CSA and turbofan code.
Bug: v8:12547
Change-Id: I054a04624d4cf1f37bc26ae4b92b6fe33408538a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3585353
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Luis Fernando Pardo Sixtos <lpardosixtos@microsoft.com>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81285}
