Fix harmless compiler warnings about unused debugging functions in treeview.c.

FossilOrigin-Name: 4d6f907712e35eddf6af36eb823c3ccdfcdff1c63b2c224b3bcf34ffec95d511

src/main.c

@@ -4116,6 +4116,7 @@ int sqlite3_test_control(int op, ...){
         sqlite3ShowWindow(0);
         sqlite3ShowWinFunc(0);
 #endif
+        sqlite3ShowSelect(0);
       }
 #endif
       break;