[turbofan] Inline Array.isArray in JSBuiltinReducer.

src/compiler/js-builtin-reducer.h

Index: src/compiler/js-builtin-reducer.h
diff --git a/src/compiler/js-builtin-reducer.h b/src/compiler/js-builtin-reducer.h
index 6ff06e3bf3874a06b12cedbed7afb55838291bf3..9dcc8b36c0e3678fefa945856e655695732447a4 100644
--- a/src/compiler/js-builtin-reducer.h
+++ b/src/compiler/js-builtin-reducer.h
@@ -55,6 +55,7 @@ class V8_EXPORT_PRIVATE JSBuiltinReducer final
                                         IterationKind kind);
   Reduction ReduceTypedArrayIteratorNext(Handle<Map> iterator_map, Node* node,
                                          IterationKind kind);
+  Reduction ReduceArrayIsArray(Node* node);
   Reduction ReduceArrayPop(Node* node);
   Reduction ReduceArrayPush(Node* node);
   Reduction ReduceDateNow(Node* node);