Created by: Steffy-zxf

update ops's unittest of elementwise_pow, elementwise_max, elementwis…

1. update elementwise_pow, elementwise_max and scale's unitests with input data type (float32 -> float64)
2. fix bug that the elementwise_pow doesn't meet threshold requirements with tackling float64 data
3. remove sqrt from op_accuracy_white_list.py
4. update the unittests of elementwise_pow, elementwise_max and elementwise_min ops that their input data shape over 100
5. test=develop
6. fix https://github.com/PaddlePaddle/Paddle/issues/22542