This is a reland of b77deeca

Changes compared to original: Add explicit narrowing casts in tests
for MSVC.

Original change's description:
> [wasm-gc] Remove abstract rtts
>
> In the latest wasm-gc spec, rtts of abstract types are no longer
> allowed. Consequently, canonical rtts of concrete types always have
> a depth of 0.
>
> Changes:
> - Change the immediate argument of rtts to a type index over a heap
>   type. Abstract it with TypeIndexImmediate in function body decoding.
>   This affects:
>   value_type.h, read_value_type(), decoding of relevant opcodes,
>   wasm subtyping, WasmInitExpr, consume_init_expr(), and
>   wasm-module-builder.cc.
> - In function-body-decoder-impl.h, update rtt.canon to always produce
>   an rtt of depth 0.
> - Pass a unit32_t type index over a HeapType to all rtt-related
>   utilities.
> - Remove infrastructure for abstract-type rtts from the wasm compilers,
>   setup-heap-internal.cc, roots.h, and module-instantiate.cc.
> - Remove ObjectReferenceKnowledge::rtt_is_i31. Remove related branches
>   from ref.test, ref.cast and br_on_cast implementations in the wasm
>   compilers.
> - Remove unused 'parent' field from WasmTypeInfo.
> - Make the parent argument optional in NewWasmTypeInfo, CreateStructMap,
>   and CreateArrayMap.
> - Use more convenient arguments in IsHeapSubtypeOf.
> - Update tests.
>
> Bug: v8:7748
> Change-Id: Ib45efe0741e6558c9b291fc8b4a75ae303146bdc
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2642248
> Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#72321}

Bug: v8:7748
Change-Id: I22b204b486fd185077cd6c7f15d492f5143f48fe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2650207
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72355}