[Regression] ValueError: Flag FLAGS_use_onednn cannot set its value through this function by commit ad9b40ecb10e2323c03b8ba2c96310307d8f8509

[FocusLuo]

1, how to reproduce:
mkdir /path_to_repo/PaddleCustomDevice/backends/intel_hpu/build
cd /path_to_repo/PaddleCustomDevice/backends/intel_hpu/build
cmake ..
make -j16
pip install --force-reinstall dist/*.whl
cd ../custom_ops
python setup.py install

export PYTHONPATH=/path_to_repo/PaddleCustomDevice/python/:/path_to_repo//PaddleCustomDevice/Paddle/test/legacy_test/:$PYTHONPATH
export GC_KERNEL_PATH=/usr/local/lib/python3.10/dist-packages/paddle_custom_device/intel_hpu/libcustom_tpc_perf_lib.so:$GC_KERNEL_PATH

cd /path_to_repo/PaddleCustomDevice/backends/intel_hpu/tests/unittests/
python test_reduce_sum.py
python test_gather_nd.py

2, when using commit c35130f, there is no issue;
but when using ad9b40e, there will have
Traceback (most recent call last):
File "/workspace/pdpd_automation/repo/PaddleCustomDevice/backends/intel_hpu/tests/unittests/test_gather.py", line 57, in test_check_output
self.check_output_with_place(self.place)
File "/workspace/pdpd_automation/repo/PaddleCustomDevice/python/tests/op_test.py", line 2237, in check_output_with_place
set_flags({"FLAGS_use_onednn": False})
File "/usr/local/lib/python3.10/dist-packages/paddle/base/framework.py", line 153, in set_flags
raise ValueError(
ValueError: Flag FLAGS_use_onednn cannot set its value through this function.

commit ad9b40e (HEAD -> develop)
Author: Yuqiang Ge 143453447+YqGe585@users.noreply.github.com
Date: Mon Aug 11 10:25:26 2025 +0800

update paddle and fix sdaa test error (#1876)

3, this regression caused about 50% INTEL_HPU Unittest cases failed

[FocusLuo]

@LeoZhao-Intel @yanfeich @JianyuLi01 @feiwan1 @fmiao2372