Split interface functions into constant, non-constant, and meta
functions. This will be useful once initializer expression decoding is
implemented as an interface for WasmFullDecoder.
Additionally, add ArrayInit() interface function (currently unused).

Bug: v8:11895
Change-Id: If076fe47871868c2d754f9c72c865f0a7f9f97d3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2964609
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75251}