[cherry-pick] fix wrong place in ut (#42488)

* fix wrong place

* skip bf16 test if not supported (#42503)

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

@@ -919,7 +919,7 @@ class TestPureFp16InferenceSaveLoad(unittest.TestCase):
 
         # load_inference_model
         paddle.enable_static()
-        exe = paddle.static.Executor(paddle.CPUPlace())
+        exe = paddle.static.Executor()
         [inference_program, feed_target_names, fetch_targets] = (
             paddle.static.load_inference_model(path, exe))
         tensor_img = x
@@ -927,8 +927,8 @@ class TestPureFp16InferenceSaveLoad(unittest.TestCase):
                           feed={feed_target_names[0]: tensor_img},
                           fetch_list=fetch_targets)
         print("pred.numpy()", pred.numpy())
-        print("results", results)
-        self.assertTrue(np.allclose(pred.numpy(), results, atol=1.e-5))
+        print("result", results[0])
+        self.assertTrue(np.array_equal(pred.numpy(), results[0]))
         paddle.disable_static()
 
     def test_inference_save_load(self):
@@ -1254,9 +1254,8 @@ class TestBf16(unittest.TestCase):
 
     def test_bf16(self):
         def func_isinstance():
-            if fluid.core.is_compiled_with_cuda():
-                cudnn_version = paddle.device.get_cudnn_version()
-                if cudnn_version is not None and cudnn_version >= 8100:
+            if fluid.core.is_compiled_with_cuda(
+            ) and fluid.core.is_bfloat16_supported(paddle.CUDAPlace(0)):
                 out_fp32 = self.train(enable_amp=False)
                 out_bf16_O1 = self.train(enable_amp=True, amp_level='O1')
                 out_bf16_O2 = self.train(enable_amp=True, amp_level='O2')