[3.12] gh-115011: Improve support of __index__() in setters of members with unsigned...

[3.12] gh-115011: Improve support of __index__() in setters of members with unsigned integer type (GH-115029) (GH-115294)

Setters for members with an unsigned integer type now support
the same range of valid values for objects that has a __index__()
method as for int.

Previously, Py_T_UINT, Py_T_ULONG and Py_T_ULLONG did not support
objects that has a __index__() method larger than LONG_MAX.

Py_T_ULLONG did not support negative ints. Now it supports them and
emits a RuntimeWarning.
(cherry picked from commit d9d6909697501a2604d5895f9f88aeec61274ab0)