* nullptr bugfix for XPU pg mode

Also a few kernels is added to xpu whitelist

* increase error msg length

This is a PR to catch up with latest xpu white list strategy
(https://github.com/PaddlePaddle/Paddle/pull/48606)
, since original list only include 'fluid' fashion names, but new list
must include 'phi' fashion as well.
Refer to paddle/phi/core/kernel_factory.cc for more details.

* [XPU] add load op into oplist.

* remove test_sampling_id_op_xpu.py

*test=kunlun

*test=kunlun