This is a reland of 79398ab0

Original change's description:
> [wasm] Further reduce the size of WasmCode
>
> Also, save dynamic allocations (plus their memory overhead).
> This is realized by storing the relocation information, source position
> table, and protected instruction information together in one "metadata"
> byte array.
> For each of the three components, we just store their size, such that
> the accessors can return the respecitive {Vector} views as before.
>
> This makes each WasmCode object 24 bytes smaller on 64-bit
> architectures. It also saves a few more bytes per code object because
> less padding is needed for the individual allocations, and each dynamic
> allocation comes with some constant memory overhead.
>
> Since the protected instructions will just be stored in a byte array
> now, some APIs are refactored to just return that byte array directly
> (instead of an array of {ProtectedInstructionData}). This also
> simplifies serialization and deserialization, and will allow for
> switching to a more compact representation in the future.
>
> Drive-by: Add some more checks to {Vector::cast} to protect against
>   undefined behaviour.
>
> R=ahaas@chromium.org
>
> Bug: v8:10254
> Change-Id: I81ca847023841110e3e52cc402fcb0349325d7af
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2078545
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#66596}

Tbr: ahaas@chromium.org
Bug: v8:10254
Change-Id: Idcdcb4f13c3eb7a3f7fb5ef8a1229103ca0ae975
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2089934Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66598}