[Eager] fix slice's input mistake (#44855)

* [Eager] fix slice's input mistake

* add tests for slice

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

@@ -635,7 +635,7 @@ class TestSliceApiEager(unittest.TestCase):
                                    axes=axes,
                                    starts=paddle.to_tensor(starts),
                                    ends=paddle.to_tensor(ends))
-
+                self.assertTrue(np.array_equal(a_1.numpy(), a_2.numpy()))
                 a_1.backward()
                 grad_truth = paddle.zeros_like(a)
                 grad_truth[-3:3, 0:2, 2:4] = 1

python/paddle/tensor/manipulation.py

@@ -208,7 +208,7 @@ def slice(input, axes, starts, ends):
                 if isinstance(item, tmp_tensor_type) else item for item in ends
             ]
         elif isinstance(ends, tmp_tensor_type):
-            etensor_t = ends.numpy()
+            tensor_t = ends.numpy()
             ends = [ele for ele in tensor_t]
             infer_flags = list(-1 for i in range(len(axes)))