[Cleanup] `to_variable` -> `paddle.to_tensor` 问题汇总

[gouzil]

背景

我们在单测中发现还有许多旧的to_variable API，没有被新的to_tensor API 替换，为了做到 API 统一，开始逐步清除to_variable API 的使用

具体例子

x = np.ones([2, 2], np.float32)
y = base.dygraph.to_variable(x)

修改后：

x = np.ones([2, 2], np.float32)
y = paddle.to_tensor(x)

任务列表

✅：已经完全迁移，所有单测都OK！ 🟢：审核完毕待合入，合入之后完全迁移！ 🔵：可认领！ 🟡：当前阶段不需要人力继续跟进，下阶段推进（大部分是精度问题） 🚧：迁移中，单测还没有过，还没有审核完。

大致正常流程为: 🔵 -> 🚧 -> 🟢 -> ✅

异常流程为: 🔵 -> 🚧 -> 🟡

### 第一阶段:（整体进展：0/19） > test 目录下文件清理

序号	文件位置	认领人	PR
🔵1	check_flags_mkldnn_ops_on_off.py check_flags_use_mkldnn.py ifelse_simple_func.py op_test.py parallel_dygraph_control_flow_same.py parallel_dygraph_mnist.py parallel_dygraph_se_resnext.py parallel_dygraph_shared_unused_var.py parallel_dygraph_sparse_embedding.py parallel_dygraph_sync_batch_norm.py
🔵2	parallel_dygraph_transformer.py seq2seq_dygraph_model.py simnet_dygraph_model.py test_activation_op.py test_adam_op.py test_adaptive_avg_pool1d.py test_adaptive_max_pool1d.py test_addmm_op.py test_affine_grid_function.py test_array_read_write_op.py
🔵3	test_assert.py test_basic_api_transformation.py test_batch_norm_op.py test_bicubic_interp_op.py test_bicubic_interp_v2_op.py test_bincount_op.py test_bmm_op.py test_bmn.py test_cache_program.py test_cast.py
🔵4	test_cholesky_op.py test_chunk_op.py test_coalesce_tensor_op.py test_complex_elementwise_layers.py test_complex_getitem.py test_complex_kron.py test_complex_matmul.py test_complex_reshape.py test_complex_sum_layer.py test_complex_trace_layer.py
🔵5	test_complex_transpose.py test_complex_variable.py test_conv2d_api.py test_conv2d_transpose_layer.py test_conv3d_transpose_layer.py test_convert_call.py test_correlation.py test_cross_op.py test_cycle_gan.py test_declarative.py
🔵6	test_detach.py test_detection.py test_dict.py test_directory_migration.py test_dot_op.py test_dropout_op.py test_dropout_op_xpu.py test_dygraph_mnist_fp16.py test_dygraph_multi_forward.py test_dygraph_weight_norm.py
🔵7	test_egr_python_api.py test_eig_op.py test_elementwise_add_op.py test_elementwise_add_op_xpu.py test_elementwise_add_op_xpu_kp.py test_elementwise_pow_op.py test_elementwise_sub_op.py test_erf_op.py test_exception.py test_fill_constant_op.py
🔵8	test_fleet_base.py test_flip.py test_for_enumerate.py test_functional_conv1d.py test_functional_conv1d_transpose.py test_functional_conv2d.py test_functional_conv2d_transpose.py test_functional_conv3d.py test_functional_conv3d_transpose.py test_gather_nd_op.py
🔵9	test_gelu_op.py test_grad_clip_minimize.py test_gradient_clip.py test_group_norm_op.py test_histogram_op.py test_ifelse.py test_imperative_auto_mixed_precision_for_eager.py test_imperative_container_layerlist.py test_imperative_container_parameterlist.py test_imperative_container_sequential.py
🔵10	test_imperative_deepcf.py test_imperative_double_grad.py test_imperative_framework.py test_imperative_gan.py test_imperative_gnn.py test_imperative_hook_for_layer.py test_imperative_layer_trainable.py test_imperative_lod_tensor_to_selected_rows.py test_imperative_mnist_sorted_gradient.py test_imperative_named_members.py
🔵11	test_imperative_ocr_attention_model.py test_imperative_optimizer.py test_imperative_optimizer_v2.py test_imperative_parallel_coalesce_split.py test_imperative_partitial_backward.py test_imperative_ptb_rnn.py test_imperative_ptb_rnn_sorted_gradient.py test_imperative_recurrent_usage.py test_imperative_reinforcement.py test_imperative_resnet.py
🔵12	test_imperative_resnet_sorted_gradient.py test_imperative_save_load_v2.py test_imperative_selected_rows.py test_imperative_selected_rows_to_lod_tensor.py test_imperative_star_gan_with_gradient_penalty.py test_imperative_trace_non_persistable_inputs.py test_imperative_transformer_sorted_gradient.py test_imperative_triple_grad.py test_imperative_using_non_zero_gpu.py test_index_select_op.py
🔵13	test_index_select_op_xpu.py test_instance_norm_op.py test_instance_norm_op_v2.py test_inverse_op.py test_inverse_op_xpu.py test_jit_save_load.py test_kron_op.py test_label_smooth_functional.py test_lac.py test_learning_rate_scheduler.py
🔵14	test_legacy_error.py test_linear_interp_op.py test_linear_interp_v2_op.py test_list.py test_loop.py test_matmul_op.py test_matmul_op_xpu.py test_matrix_power_op.py test_mean_op.py test_merged_adam_op.py
🔵15	test_merged_adam_op_xpu.py test_meshgrid_op.py test_mnist.py test_mobile_net.py test_mse_loss.py test_nansum_api.py test_nn_functional_hot_op.py test_nonzero_api.py test_one_hot_v2_op.py test_one_hot_v2_op_xpu.py
🔵16	test_op_function_generator.py test_optimizer_in_control_flow.py test_paddle_imperative_double_grad.py test_partial_program.py test_pylayer.py test_reduce_op.py test_regularizer.py test_regularizer_api.py test_reinforcement_learning.py test_repeat_interleave_op.py
🔵17	test_roll_op.py test_rot90_op.py test_save_load.py test_scatter_nd_op.py test_scatter_op.py test_se_resnet.py test_sentiment.py test_slice_op.py test_smooth_l1_loss.py test_softmax_mask_fuse_op.py
🔵18	test_softmax_mask_fuse_upper_triangle_op.py test_solve_op.py test_stack_op.py test_tensor_shape.py test_traced_layer_err_msg.py test_transpose_op.py test_tril_triu_op.py test_unfold_op.py test_unfold_op_xpu.py test_unstack_op.py
🔵19	test_where_op.py test_where_op_xpu.py test_word2vec.py transformer_dygraph_model.py

认领方式

请大家以 comment 的形式认领任务，如：

【报名】：1、3、12-13

多个任务之间需要使用顿号分隔，报名多个连续任务可用横线表示，如 2-5 PR 提交格式：在 PR 的标题中以 【Cleanup to_variable No.】 开头，注明任务编号

看板信息

任务数量	🔵可认领	🚧迁移中	🟢待合入	✅完成	🟡下阶段推进	完成率
19	19	0	0	0	0	0.0%

[gouzil]

任务合并至 https://github.com/PaddlePaddle/Paddle/issues/61385