Design doc: bit.ly/3jEVgzz

We separate the internal representation of function references in Wasm
from their JSFunction-based (external) representation. This improves
performance of call_ref by requiring less indirections to load the
context and call target from a function reference. In the boundary
between wasm and JS/the C API, we add transformations between the two
representations.

Detailed changes:
- Introduce WasmInternalFunction, containing fields required by
  call_ref, as well as a reference to the corresponding
  WasmExternalFunction. Add a reference to the WasmInternalFunction in
  WasmFunctionData. The {WasmInternalFunction::FromExternal} helper
  extracts the internal out of an external function.
- Change {WasmInstanceObject::external_functions()} to internal
  functions.
- Change wasm function tables to contain internal functions.
- Change the following code to use internal functions:
  - call_ref in liftoff and Turbofan
  - function type checks in liftoff and Turbofan
  - CallRefIC and GenericJSToWasmWrapper builtins
  - {InitExprInterface::RefFunc}
  - module-compiler.cc in {ProcessTypeFeedback}
  - In module-instantiate.cc, in function-rtt creation.
- Add transformations between internal and external functions in:
  - WasmWrapperGraphBuilder::{ToJS, BuildUnpackObjectWrapper, FromJS,
    BuildJSToJSWrapper}.
  - debug-wasm-objects.cc in {FunctionProxy::Get},
    {WasmValueObject::New} and {AddWasmTableObjectInternalProperties}.
  - runtime-wasm.cc in ReplaceWrapper
  - the C and JS APIs
  - module-instantiate.cc, in import and export processing, as well as
    {InitializeIndirectFunctionTables}
  - WasmTableObject::{IsValidElement, SetFunctionTableEntry}
  - {WasmGlobalObject::SetFuncRef}
- Simplify body descriptors of WasmExternalFunction variants.
- Adjust tests.

Bug: v8:11510

Change-Id: I8377f46f55c3771391ae1c5c8201a83854ee7878
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3277878Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78068}