[turbofan] Fix lowering of Number.isNaN().

src/compiler/js-builtin-reducer.cc

Index: src/compiler/js-builtin-reducer.cc
diff --git a/src/compiler/js-builtin-reducer.cc b/src/compiler/js-builtin-reducer.cc
index 66c212dfcb71a3d3f45ba6411736558a378fb6e7..40aaef91f9b5ace09b21913ae398b18cc0428753 100644
--- a/src/compiler/js-builtin-reducer.cc
+++ b/src/compiler/js-builtin-reducer.cc
@@ -1513,6 +1513,11 @@ Reduction JSBuiltinReducer::ReduceNumberIsInteger(Node* node) {
 // ES6 section 20.1.2.4 Number.isNaN ( number )
 Reduction JSBuiltinReducer::ReduceNumberIsNaN(Node* node) {
   JSCallReduction r(node);
+  if (r.InputsMatchZero()) {
+    // Number.isNaN() -> #false
+    Node* value = jsgraph()->FalseConstant();
+    return Replace(value);
+  }
   // Number.isNaN(a:number) -> ObjectIsNaN(a)
   Node* input = r.GetJSCallInput(0);
   Node* value = graph()->NewNode(simplified()->ObjectIsNaN(), input);