cbo/debug: fix Print with missing Stats (#7512)

Author: yumkam

ydb/library/yql/core/cbo/cbo_optimizer_new.cpp

@@ -101,11 +101,10 @@ void TJoinOptimizerNode::Print(std::stringstream& stream, int ntabs) {
     }
     stream << "\n";
 
-    for (int i = 0; i < ntabs; i++){
-        stream << "    ";
-    }
-
     if (Stats) {
+        for (int i = 0; i < ntabs; i++){
+            stream << "    ";
+        }
         stream << *Stats << "\n";
     }