add r50 dynamic fp16 train for benchmark

test_tipc/config/ResNet/ResNet50_train_ampfp16_infer_python.txt

@@ -51,6 +51,6 @@ inference:python/predict_cls.py -c configs/inference_cls.yaml
 null:null
 null:null
 ===========================train_benchmark_params==========================
-batch_size:128
-fp_items:amp_fp16
+batch_size:128|256
+fp_items:ampfp16
 epoch:1

test_tipc/config/ResNet/ResNet50_train_purefp16_infer_python.txt

@@ -51,6 +51,6 @@ inference:python/predict_cls.py -c configs/inference_cls.yaml
 null:null
 null:null
 ===========================train_benchmark_params==========================
-batch_size:128
-fp_items:pure_fp16
+batch_size:128|256
+fp_items:purefp16
 epoch:1