change rtol to 1e-4 when compare model with different optimize level (#138)

Author: XiaobingSuper

tests/cpu/test_weight_prepack.py

@@ -294,7 +294,7 @@ def _test_imagenet_model(self, model):
                     loss2.backward()
                     ipex_optimizer2.step()
             self.assertEqual(y, y1)
-            self.assertEqual(y1, y2, rtol=1e-5, atol=1e-3)
+            self.assertEqual(y1, y2, rtol=1e-4, atol=1e-3)
             self.assertEqual(loss, loss1)
             self.assertEqual(loss1, loss2, rtol=1e-5, atol=1e-3)