[turbofan] Quickfix for fround built-in lowering.

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 b5caf9f1fe6ecc3824a487de3359f76bc038d6a4..be7d8b59ef2ceb7dafca510911eba37d27a8f767 100644
--- a/src/compiler/js-builtin-reducer.cc
+++ b/src/compiler/js-builtin-reducer.cc
@@ -172,7 +172,7 @@ Reduction JSBuiltinReducer::ReduceMathFloor(Node* node) {
 // ES6 draft 08-24-14, section 20.2.2.17.
 Reduction JSBuiltinReducer::ReduceMathFround(Node* node) {
   JSCallReduction r(node);
-  if (r.InputsMatchOne(Type::Number())) {
+  if (r.InputsMatchOne(Type::NumberOrUndefined())) {
     // Math.fround(a:number) -> TruncateFloat64ToFloat32(a)
     Node* value =
         graph()->NewNode(machine()->TruncateFloat64ToFloat32(), r.left());