[turbofan] Introduce JSCallForwardVarargs operator.

src/compiler/js-typed-lowering.h

Index: src/compiler/js-typed-lowering.h
diff --git a/src/compiler/js-typed-lowering.h b/src/compiler/js-typed-lowering.h
index 20f35f1fe144c954665250ce45eec782c943c57b..9a037cf3c154b1e3005370f74b5a6646bfe312c0 100644
--- a/src/compiler/js-typed-lowering.h
+++ b/src/compiler/js-typed-lowering.h
@@ -71,6 +71,7 @@ class V8_EXPORT_PRIVATE JSTypedLowering final
   Reduction ReduceJSToObject(Node* node);
   Reduction ReduceJSConvertReceiver(Node* node);
   Reduction ReduceJSCallConstruct(Node* node);
+  Reduction ReduceJSCallForwardVarargs(Node* node);
   Reduction ReduceJSCallFunction(Node* node);
   Reduction ReduceJSForInNext(Node* node);
   Reduction ReduceJSLoadMessage(Node* node);