* [Enhancement] Update reduce operations to support clear option in sum and abs sum (#436)
* Modified reduce_sum and reduce_absmax functions to include a clear parameter, allowing for accumulation on existing values.
* Updated ReduceOp::Lower method to handle initialization and buffer duplication based on the clear flag for sum and abs sum operations.
* Added new tests for reduce_sum and reduce_max with clear functionality to ensure correctness in various scenarios.
* Enhanced documentation for reduce functions to clarify the behavior of the clear parameter.
* lint fix
* Update tensor type annotations in test_tilelang_transform_annotate_device_regions.py from Buffer to Tensor
* Update tensor type in reduce sum tests from float16 to float32 for improved precision
* [Feature] Implement CumSum operation in TileLang
* Added CumSumOp class for cumulative sum operations, including argument validation and lowering logic.
* Introduced CumSum2D template for CUDA, supporting both forward and reverse cumulative sums.
* Created tests for CumSum functionality in shared memory and fragment contexts.
* Updated language interface to include cumsum operation, enhancing the reduction capabilities of TileLang.
* Refactored reduce.py to support cumsum functionality with appropriate memory allocation and copying mechanisms.
* lint fix
Lei Wang