Fix inconsisteny between Python and JIT power operation (#62842)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/62842
Test Plan:
Wrote unit test TestAtenPow to test behavior of aten::pow when:
1. base is int, exponent is int
2. base is int, exponent is float
3. base is float, exponent is int
4. base is float, exponent is float
Specifically, we test that when base is zero and exponent is negative, we raise error. In all other cases, we expect behavior to be the same as the result returned by Python.
It is because the cpp code relies on overloading, we need to make sure all combinations of types give us the expected result.
Reviewed By: zhxchen17
Differential Revision: D30146115
Pulled By: szewaiyuen7
fbshipit-source-id: dc661897ad38da286ee454120fbe41314b7f2995
