Revert of [turbofan] Remove left-over change bits from ChangeLowering.

src/compiler/change-lowering.h

Index: src/compiler/change-lowering.h
diff --git a/src/compiler/change-lowering.h b/src/compiler/change-lowering.h
index a79cb9c7a60147dea6893ef1f39e97a2c3d188d2..064b38fd5bd1e94f6783dcd9faa9a60a9b49de6e 100644
--- a/src/compiler/change-lowering.h
+++ b/src/compiler/change-lowering.h
@@ -27,11 +27,24 @@
   Reduction Reduce(Node* node) final;
 
  private:
+  Node* SmiShiftBitsConstant();
+
+  Node* ChangeInt32ToSmi(Node* value);
+  Node* ChangeSmiToWord32(Node* value);
+  Node* ChangeUint32ToFloat64(Node* value);
+
+  Reduction ReduceChangeBitToBool(Node* value, Node* control);
+  Reduction ReduceChangeBoolToBit(Node* value);
+  Reduction ReduceChangeInt31ToTagged(Node* value, Node* control);
+  Reduction ReduceChangeTaggedSignedToInt32(Node* value);
+
   Reduction ReduceLoadField(Node* node);
   Reduction ReduceStoreField(Node* node);
   Reduction ReduceLoadElement(Node* node);
   Reduction ReduceStoreElement(Node* node);
   Reduction ReduceAllocate(Node* node);
+
+  Reduction ReduceObjectIsSmi(Node* node);
 
   Node* ComputeIndex(const ElementAccess& access, Node* const key);
   Graph* graph() const;