gh-120389: Add PyLong_FromInt64() and PyLong_AsInt64() (#120390)

Add new functions to convert C <stdint.h> numbers from/to Python int:

* PyLong_FromInt32()
* PyLong_FromUInt32()
* PyLong_FromInt64()
* PyLong_FromUInt64()
* PyLong_AsInt32()
* PyLong_AsUInt32()
* PyLong_AsInt64()
* PyLong_AsUInt64()