!10028 adjust st of resnet50 in ascend pynative to gpu pynative

From: @lianliguang
Reviewed-by: @kisnwang,@zhoufeng54
Signed-off-by: @zhoufeng54

tests/st/pynative/test_pynative_resnet50_gpu.py

@@ -412,6 +412,6 @@ def test_pynative_resnet50():
         end_time = time.time()
         cost_time = end_time - start_time
         print("======step: ", step, " loss: ", loss_output.asnumpy(), " cost time: ", cost_time)
-        if step > 1 and cost_time > 0.15:
+        if step > 1 and cost_time > 0.18:
             exceed_num = exceed_num + 1
-    assert exceed_num < 18
+    assert exceed_num < 20