[turbofan ] Simplify reference equal if both inputs are constants

src/compiler/simplified-operator-reducer.h

Index: src/compiler/simplified-operator-reducer.h
diff --git a/src/compiler/simplified-operator-reducer.h b/src/compiler/simplified-operator-reducer.h
index 831090ac9f4c64c0239199a06e5dfa8a17c4bf70..979a3d03995ef851f2772db3a8daded8fe48e2d0 100644
--- a/src/compiler/simplified-operator-reducer.h
+++ b/src/compiler/simplified-operator-reducer.h
@@ -25,6 +25,8 @@ class SimplifiedOperatorReducer final : public Reducer {
   Reduction Reduce(Node* node) final;
 
  private:
+  Reduction ReduceReferenceEqual(Node* node);
+
   Reduction Change(Node* node, const Operator* op, Node* a);
   Reduction ReplaceFloat64(double value);
   Reduction ReplaceInt32(int32_t value);