gh-156695: Improve accuracy of complex powers with small negative integer exponents

[Aniketsy]

Fixes #156695

>>> import math
>>> z = complex(float.fromhex('0x1.47e9c711723f5p+81'),
...            float.fromhex('0x1.38afd1168e49fp+85'))
>>> ref = complex(float.fromhex('0x0.4000000000000p-1022'),
...            float.fromhex('0x0.3ffffffffffffp-1022'))
>>> z ** -12
0j
>>> abs((z**-12 - ref).real) / math.ulp(ref.real)
1125899906842624.0
>>> 0.0j ** 0
(1+0j)

• Issue: Improve accuracy for complex powers with small negative integer exponents #156695