* rm fluid gpu_launch_config

* fix type

resort .cu headers, set clang-format not sort include block and consider .cu as main source file (#43633)

add a inner loop for index_select_grad_init() in index_select op when dealing with large-shape data (#41563)

* replace for with CUDA_KERNEL_LOOP for index_select_grad_init() in index_select op

* use CUDA_KERNEL_LOOP_TYPE

* fix code style

* replace index_select_grad_init with SetConstant

* limit grid dim for index select

* mv LimitGridDim into gpu_launch_config.h

* fix conflicts

* fix conflicts

* fix code style

* set block to 256

* fix grid setting

* set dtype of block_dim to unsigned int

* fix uncontrolled randomness of op

* fix bugs

* [PHI] Migrate index_select op

* [PHI] Fix bug in test_variable

* [PHI] migrate index_select op