[Dy2St]Fix test_lac and test_sentiment UT error (#52109)

test/dygraph_to_static/test_lac.py

@@ -79,7 +79,7 @@ class DynamicGRU(paddle.nn.Layer):
             # input_ = inputs[:, j:j+1, :]  # original code
             input_ = paddle.slice(inputs, axes=[1], starts=[j], ends=[j + 1])
             input_ = paddle.reshape(input_, [-1, input_.shape[2]])
-            hidden, reset, gate = self.gru_unit(input_, hidden)
+            hidden, reset = self.gru_unit(input_, hidden)
             hidden_ = paddle.reshape(hidden, [-1, 1, hidden.shape[1]])
             res.append(hidden_)