[WIP] NumberToString operator in TF.

src/compiler/js-typed-lowering.cc

Index: src/compiler/js-typed-lowering.cc
diff --git a/src/compiler/js-typed-lowering.cc b/src/compiler/js-typed-lowering.cc
index 01122bdfb4b9cfa6c9db34a63f1d12a8b07a7a02..bd14a938accf201589f2ed47717d92525ba732e0 100644
--- a/src/compiler/js-typed-lowering.cc
+++ b/src/compiler/js-typed-lowering.cc
@@ -959,7 +959,10 @@ Reduction JSTypedLowering::ReduceJSToStringInput(Node* input) {
   if (input_type->Is(Type::Null())) {
     return Replace(jsgraph()->HeapConstant(factory()->null_string()));
   }
-  // TODO(turbofan): js-typed-lowering of ToString(x:number)
+  if (input_type->Is(Type::Number())) {
+    return Replace(graph()->NewNode(simplified()->NumberToString(), input,
+                                    jsgraph()->Constant(10)));
+  }
   return NoChange();
 }