[Speed] performance: remove "pure python" pickle benchmarks?

[Serhiy Storchaka]

On 04.04.17 01:21, Victor Stinner wrote:
> In benchmarks slower in Python 3.7 compared to 2.7 at
> https://speed.python.org/comparison/ I found pickle_pure_python and
> unpickle_pure_python. These benchmarks test the pure Python
> implementation of the pickle protocol.
>
> I don't see the point of testing the pure Python implementation, since
> the C accelerator (_pickle) is always used by default in Python 3. I
> propose to remove this benchmark. What do you think?

I consider it as a benchmark of Python interpreter itself. And indeed, 
they show a progress from 3.5 to 3.7. A slow regression in unpickling in 
3.5 may be related to adding more strong validation (but may be not 
related).

Unfortunately the Python code is different in different versions. Maybe 
write a single cross-version pickle implementation and use it with these 
benchmarks?