[issue27786] longobject.c: simplify x_sub(), inline _PyLong_Negate()

[STINNER Victor]

STINNER Victor added the comment:

> I would add a comment as to why the assertion is there, otherwise it seems somewhat random that it exists.

Hum. Maybe it's even better to remove the assertion :-)

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue27786>
_______________________________________