[Speed] Update Django from 1.11 to 2.0? What about Python 2.7 and PyPy2?

[Victor Stinner]

Hi,

I regularly update requirements of the performance benchmark suite.
Django 2.0 is now proposed, but it's incompatible with Python 2.7 and
PyPy2.

* Is it ok to skip the django_template benchmark on Python 2.7 and PyPy2?
* Should we add a different benchmark?
* Or test different Django version depending on the Python version?

I'm fine with testing Django 1.11 on Python 2.7 and test Django >= 2.0
on Python 3, but maybe others have different opinion on that?

The main question is the expected behaviour when comparing Python2 and
Python3 with performance on the Django template benchmark.

Victor