[turbofan] Introduce a dedicated CheckMaps simplified operator.

src/compiler/load-elimination.h

Index: src/compiler/load-elimination.h
diff --git a/src/compiler/load-elimination.h b/src/compiler/load-elimination.h
index 72da0d38a0bc4ee52e1bdbbe0029b5769e0ec691..5c8002dcd59bbe10b1bba21e7aaecd1371777a7e 100644
--- a/src/compiler/load-elimination.h
+++ b/src/compiler/load-elimination.h
@@ -149,6 +149,8 @@ class LoadElimination final : public AdvancedReducer {
     ZoneVector<AbstractState const*> info_for_node_;
   };
 
+  Reduction ReduceCheckMaps(Node* node);
+  Reduction ReduceTransitionElementsKind(Node* node);
   Reduction ReduceLoadField(Node* node);
   Reduction ReduceStoreField(Node* node);
   Reduction ReduceLoadElement(Node* node);