[turbofan] Do not replace actual duplicates when value numbering

src/compiler/value-numbering-reducer.h

Index: src/compiler/value-numbering-reducer.h
diff --git a/src/compiler/value-numbering-reducer.h b/src/compiler/value-numbering-reducer.h
index f52e13b45c98a044c13fa4d80bed2f65b20dd53b..521ce59f20e84f301a8ad0f3ee78f112b992d094 100644
--- a/src/compiler/value-numbering-reducer.h
+++ b/src/compiler/value-numbering-reducer.h
@@ -24,6 +24,7 @@ class V8_EXPORT_PRIVATE ValueNumberingReducer final
  private:
   enum { kInitialCapacity = 256u };
 
+  Reduction ReplaceIfTypesMatch(Node* node, Node* replacement);
   void Grow();
   Zone* temp_zone() const { return temp_zone_; }
   Zone* graph_zone() const { return graph_zone_; }