Avoid printing "rowid_filter_skipped" in optimizer trace if no rowid filter

There is no point in saying something is skipped when it does not exists.

Author: montywi

mysql-test/main/opt_trace.result

@@ -4134,7 +4134,6 @@ explain delete t0,t1 from t0, t1 where t0.a=t1.a and t1.a<3	{
                           "rec_per_key_stats_missing": true,
                           "used_range_estimates": false,
                           "cause": "not better than ref estimates",
-                          "rowid_filter_skipped": "worst/max seeks clipping",
                           "rows": 2,
                           "cost": 3.003514767,
                           "chosen": true

sql/sql_select.cc

@@ -8704,8 +8704,11 @@ best_access_path(JOIN      *join,
         if (!(records < s->worst_seeks &&
               records <= thd->variables.max_seeks_for_key))
         {
-          // Don't use rowid filter
-          trace_access_idx.add("rowid_filter_skipped", "worst/max seeks clipping");
+          if (table->range_rowid_filter_cost_info_elems)
+          {
+            // Don't use rowid filter
+            trace_access_idx.add("rowid_filter_skipped", "worst/max seeks clipping");
+          }
           filter= NULL;
         }
         else