[wasm] Introduce instance types for WebAssembly.* objects.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 95e67e5b1a68eb6ae0b8e8473724eee8230b9ea1..994827bcd62bac44a0ff6a8285ff2a09f3b0086e 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -7721,10 +7721,10 @@ MaybeLocal<Proxy> Proxy::New(Local<Context> context, Local<Object> local_target,
 }
 
 Local<String> WasmCompiledModule::GetWasmWireBytes() {
-  i::Handle<i::JSObject> obj =
-      i::Handle<i::JSObject>::cast(Utils::OpenHandle(this));
+  i::Handle<i::WasmModuleObject> obj =
+      i::Handle<i::WasmModuleObject>::cast(Utils::OpenHandle(this));
   i::Handle<i::WasmCompiledModule> compiled_part =
-      i::handle(i::WasmCompiledModule::cast(obj->GetEmbedderField(0)));
+      i::handle(i::WasmCompiledModule::cast(obj->compiled_module()));
   i::Handle<i::String> wire_bytes(compiled_part->module_bytes());
   return Local<String>::Cast(Utils::ToLocal(wire_bytes));
 }
@@ -7760,10 +7760,10 @@ MaybeLocal<WasmCompiledModule> WasmCompiledModule::FromTransferrableModule(
 }
 
 WasmCompiledModule::SerializedModule WasmCompiledModule::Serialize() {
-  i::Handle<i::JSObject> obj =
-      i::Handle<i::JSObject>::cast(Utils::OpenHandle(this));
+  i::Handle<i::WasmModuleObject> obj =
+      i::Handle<i::WasmModuleObject>::cast(Utils::OpenHandle(this));
   i::Handle<i::WasmCompiledModule> compiled_part =
-      i::handle(i::WasmCompiledModule::cast(obj->GetEmbedderField(0)));
+      i::handle(i::WasmCompiledModule::cast(obj->compiled_module()));
 
   std::unique_ptr<i::ScriptData> script_data =
       i::WasmCompiledModuleSerializer::SerializeWasmModule(obj->GetIsolate(),