[turbofan] Introduce LoadFunctionPrototype simplified operator.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 99c8fa887267fdf0358191a23aa197158d81aad6..5594169a9a3d77763e1119bc32b14723fb8c9117 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -1730,6 +1730,10 @@ Type* Typer::Visitor::TypeStoreTypedElement(Node* node) {
   return nullptr;
 }
 
+Type* Typer::Visitor::TypeLoadFunctionPrototype(Node* node) {
+  return Type::NonInternal();
+}
+
 Type* Typer::Visitor::TypeObjectIsCallable(Node* node) {
   return TypeUnaryOp(node, ObjectIsCallable);
 }