Polish unittest test_decoupled_py_reader (#32832)

* polish test decoupled py reader

* remove bin file

python/paddle/fluid/tests/unittests/test_decoupled_py_reader.py

@@ -19,9 +19,9 @@ import time
 import six
 import unittest
 
-EPOCH_NUM = 20
-BATCH_SIZE = 32
-BATCH_NUM = 20
+EPOCH_NUM = 5
+BATCH_SIZE = 16
+BATCH_NUM = 10
 CLASS_NUM = 10
 
 
@@ -29,7 +29,7 @@ def random_reader():
     np.random.seed(1)
     for i in range(BATCH_SIZE * BATCH_NUM):
         image = np.random.random([784])
-        label = np.random.random_integers(low=0, high=CLASS_NUM - 1)
+        label = np.random.randint(low=0, high=CLASS_NUM)
         yield image, label