[issue39434] Add float __floordiv__ fast path

[Dong-hee Na]

Dong-hee Na <donghee.na92 at gmail.com> added the comment:

And on the other side,

>>> 3.8 // 0.0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ZeroDivisionError: float divmod()

I think that people expect 
ZeroDivisionError: float floor division by zero

not the current message.
I caught this optimization issue during I investigate about the error message.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue39434>
_______________________________________