!13757 fix ST failure of resnet thor

From: @wangmin0104
Reviewed-by: @sunnybeike,@xsmq
Signed-off-by: @xsmq

tests/st/networks/models/resnet50/src_thor/dataset.py

@@ -72,8 +72,8 @@ def create_dataset(dataset_path, do_train, repeat_num=1, batch_size=32):
 
     type_cast_op = C2.TypeCast(mstype.int32)
 
-    data_set = data_set.map(operations=trans, input_columns="image", num_parallel_workers=8)
-    data_set = data_set.map(operations=type_cast_op, input_columns="label", num_parallel_workers=8)
+    data_set = data_set.map(operations=trans, input_columns="image", num_parallel_workers=24)
+    data_set = data_set.map(operations=type_cast_op, input_columns="label", num_parallel_workers=24)
 
     # apply batch operations
     data_set = data_set.batch(batch_size, drop_remainder=True)