-fix fluid-lite-subgraph x86 compile error
    - Replace FLAGS with environment variables

test=develop

add clear for tensor

* fix op inputs and outputs type, test=develop

optimize softmax cuda kernel

* Remove GEMM padding in fc_compute.
test=develop

* Write a common ParallelFor function to run the for loop in parallel.

* Add the codes of padding GEMM back in fc.

* Refine the code of fc when padding_weight is false to avoid the definition of temporary Tensor.

* Refine the unit test of fc and add testing case of padding and parallel.
test=develop

* Enable more test cases in common fc unittest, including padding and parallel for x86 target.

* Remove the fc test under kernels/x86.
test=develop

* Disable relu in test of fc for non-x86 target.
test=develop

* Change the eps of arm.
test=develop

* Support multiple types for XPU and NPU op bridges

* Add lookup_table, gather, slice, stack and scale op bridges for supporting BERT

* Fix the definition of lookup_table kernel for X86

test=develop

add sequence_pool_concat fuse pass

add fuse kernel

test=develop

test=develop

add var_conv_2d + relu fuse pass

* [XPU] add transpose bridge and unit test

test=develop

* optimize content-dnn cuda kernel

* feature: update fpga kernel patch

* [ARM] change global pooling choose kernel policy, test=develop

* Support Mask RCNN2 (#2588)

* add reshape opencl kernel && optimise conv 1x1 ,test=develop

* add reshape opencl kernel && optimise conv 1x1 &&code style ,test=develop

* add reshape opencl kernel && optimise conv 1x1 &&code style ,test=develop

[LITE][OPENCL] Add relu image2d kernel unit test, Fix conv2d_1x1, relu, layout using new Image2D Layout (#2564)

* add 3 layout for opencl image. test=develop

* add relu image2d test. test=develop

* [LITE][OPENCL] Add depthwise_conv_3x3 opencl kernel

* [LITE][OPENCL] Add depthwise_conv_3x3 opencl kernel. test=develop

* [LITE][OPENCL] Add Pool opencl kernel. test=develop

optimize search_grnn

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

* add opencl conv1x1 image impl and unit test pass with relu & bias,
add layout_compute --> buffer2image float32 --> with unit test pass
suite checked test for more situation , test=develop

* add opencl conv1x1 image impl and unit test pass with relu & bias,
add layout_compute --> buffer2image float32 --> with unit test pass
suite checked test for more situation , test=develop

* fix white space cpp lint , test=develop

test=develop

test=develop

test=develop

* 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

- fix fill_constant bug.
- cast op support int64_t->int32_t

update cuda kernels to run content-dnn model