fix eager_gen node bug (#41165)

paddle/fluid/eager/auto_code_generator/final_state_generator/eager_gen.py

@@ -1255,7 +1255,7 @@ class DygraphNodeGenerator(DygraphFunctionGeneratorBase):
             if num_outputs == 1:
                 get_tensor_str = f"auto& {transformed_tensor_name} = grad_api_result;"
             else:
-                get_tensor_str = f"auto& {transformed_tensor_name} = grad_api_result[{fwd_position}];"
+                get_tensor_str = f"auto& {transformed_tensor_name} = grad_api_result[{grad_api_position}];"
             get_outputs_str += get_tensor_str + "\n"
 
         # Prepare for Node Creation if Necessary

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

@@ -325,8 +325,6 @@ class TestDygraphInplaceFlatten(TestDygraphInplace):
         return var.flatten_()
 
 
-"""
-# TODO: need to fix bug
 class TestDygraphInplaceScatter(TestDygraphInplace):
     def init_data(self):
         self.input_var_numpy = np.array([[1, 1], [2, 2], [3, 3]])
@@ -345,7 +343,6 @@ class TestDygraphInplaceScatter(TestDygraphInplace):
             [[1, 1], [2, 2], [3, 3], [4, 4]], dtype='float32')
 
         return paddle.scatter_(var, index, updates, overwrite=False)
-"""
 
 
 class TestDygraphInplaceElu(TestDygraphInplace):