Changes:
- Rename IsSignatureEqual -> MatchesSignature for consistency
- Add WasmInstanceObject field to WasmTableObject.
- Improve some error messages related to tables in
  function-body-decoder-impl.h.
- Introduce WasmTable::IsValidTableType. Use it wherever appropriate.
- Overload equality operators in HeapType to work with
  HeapType::Representation.
- Rename DynamicTypeCheckRef -> TypecheckJSObject.
- Handle WasmCapiFunctions in TypecheckJSObject.
- Use TypecheckJSObject in WasmTableObject::IsValidElement.
- A few more minor improvements.

Bug: v8:9495
Change-Id: I2867dd3486d7c31717ac26b87a50e15cf2b898be
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2416491
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70001}