MDEV-18810: Optimizer trace typo: cumulateed_index_scan_cost

Fixed the typo and updated the test results

mysql-test/main/opt_trace.result

@@ -2931,7 +2931,7 @@ explain select * from t1 where pk = 2 and a=5 and b=1	{
                         {
                           "index": "pk",
                           "index_scan_cost": 1.0023,
-                          "cumulateed_index_scan_cost": 1.0023,
+                          "cumulated_index_scan_cost": 1.0023,
                           "disk_sweep_cost": 0.9008,
                           "cumulative_total_cost": 1.9031,
                           "usable": true,

mysql-test/main/opt_trace_index_merge_innodb.result

@@ -141,7 +141,7 @@ explain select * from t1 where pk1 != 0  and key1 = 1	{
                         {
                           "index": "key1",
                           "index_scan_cost": 1.0001,
-                          "cumulateed_index_scan_cost": 1.0001,
+                          "cumulated_index_scan_cost": 1.0001,
                           "disk_sweep_cost": 1.0014,
                           "cumulative_total_cost": 2.0015,
                           "usable": true,

sql/opt_range.cc

@@ -6842,7 +6842,7 @@ static bool ror_intersect_add(ROR_INTERSECT_INFO *info,
   }
 
   info->total_cost= info->index_scan_costs;
-  trace_costs->add("cumulateed_index_scan_cost", info->index_scan_costs);
+  trace_costs->add("cumulated_index_scan_cost", info->index_scan_costs);
   DBUG_PRINT("info", ("info->total_cost: %g", info->total_cost));
   if (!info->is_covering)
   {