* rm grad code

* add mul_grad, test=develop

* add sgd op, test=develop

* test=develop

* add backend

* add kernel

* add grad kernel

* add mean op, test=develop

* split forward and backward, test=develop

* add lookup_dequant_op

* add sequence_conv op and arm kernel

* add test, test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* modify code style. test=develop

* fix ut, test=develop

* delete unused code, test=develop

* feat: add lstm op && kernel
      test=develop

fix: move quant op to basic

add sequence_pool_concat fuse pass

add fuse kernel

* Support Mask RCNN2 (#2588)

[LITE][NPU][XPU] Refine subgraph pass, and support NPU/XPU model generation at execution time (#2576)

* add arm split lod tensor, test=develop

* add arm merge lod tensor, test=develop

* update split merge lod tensor, test=develop

* add reduce_prob op, test=develop

* support mask_rcnn succeed, test=develop

* arrange ops&kernels to support basic models
* add relu and iocopy into basic
* add fusion_elementwise_activation_ops into basic
* add dropout,layout,io_copyonce kernel&op into basic 

test=develop

* add x86 op and kernel : search_fc and sequence_topk_avg_pooling   for content-dnn model test=develop

* [X86] add attention_padding_mask op, x86 kernel and unit test

test=develop

* [CUDA] add attention_padding_mask cuda kernel and unit test

test=develop

add search_group_padding op and x86 kernel

* [X86][CUDA] add sequence_arithmetic op , x86 kernel, cuda kernel and unit test

test=develop

* add sequence_arithmetic cuda kernel unit test

test=develop

* add search_seq_depadding x86 and cuda
* add match_matrix_tensor x86
* add search_grnn x86, no test

- add var_conv_2d op

- add var_conv_2d x86 kernel

- add var_conv_2d x86 test

* update lookup_table arm x86, test=develop

* add lookup_table_v2_op for compatibility, test=develop

- add sequence_reverse op

- add sequence_reverse kernel for x86 and cuda

- add sequence_reverse_test for x86 and cuda

- add sequence_concat op

- add sequence_concat kernel for x86 and cuda

- add sequence_concat_test for x86 and cuda

* move multiclass_nms kernel back to host test=develop

* move layer_norm OP and arm_kernel into extra type since it's added after release/v2.0-beta1 and not related with CV test=develop

* fix code_style test=develop

We have changed 11 arm_kernels into extra type in #2347 , which has caused test_compiling failure. In this PR , we move their 11 related arm_kernel_test into build_extra=ON

* add channel_wise_dequantized_max_abs op and ChannelWiseDequantOpFuser, test=develop

* fix step rnn model run bugs test=develop

* move some basic ops into extra type to reduce library size test=develop (#2347)

* Add DeleteQuantOpFuser
* Add fake_quantize_dequantize_moving_avg_abs_max_op
* Add DeleteQuantDequantOpFuser

* feat: add beam_search_special function for support nlp model

* fix: add beam_search_compute kernel input and output

* feat: add assign op & copy_compute kernel

* feat: add fill_const_batch_size_like op & kernel

* feat: add layer_norm op and kernel and ut

* fix: fix some bugs
    fix mul_op infer_shape bug when x_dim_idx = 2, x_dims.size()=3 & y_dim_idx = 1, y_dims.size()=2
    fix elementwise_compute bug when y axis is all 1
    fix beam_search choose math_func wrong bug
    fix layer_norm get attr bug
    fix fill_constant_batch_size_like shape_set bug

* feat: add gather op and kernel & and transform ut

* feats: add ops and fix bugs to support transformer op
       fix type_cast passes to skip `while`
       fix elementwise infer_shape bug when x.dims=3 and y.dims={1} & axis=0
       fix lookup_table compute bug
       fix read_from_array/beam_search/increment/compate/gather ops data_type problems

* fix:
    transfomer ut add word read inferface
    fix copy/gather/norm/layer_norm include path problem

* fix:debug info

* fix: fix input reshape bug

* fix: fix norm bug

* style: style fix & test=develop

* style: fix operators cmakelist

* style: fix operators cmakelist; test=develop

* fix and test=develop

* fix and test=develop

* style: style fix; test=develop

* add conv int8 support(in condition which the input or output channel not be the times of 4)
add add_kernel for cuda.

* can run yolov3 fp32
test=develop

* 1. fix bug with yolov3 run
test=develop

* can run yolov3 int8 test=develop