2to3 refactor broke test_perf.py

#4384

when run in HEAD mode, checking out the test_perf.py revision in git master
should run without issues no matter what version of pandas you have checked out
(at least as far back as 9.1, probably further).

Now that the script imports pandas.compat, it's broken for anything older
then a couple of weeks.

[jtratner]

probably will only work for Python 2 though.

[jreback]

python 2 only is ok
this is just run by devs

[jreback]

closed by #4478