[issue31415] Add -X option to show import time

[INADA Naoki]

INADA Naoki added the comment:

> Actually it is easy. You need just one global integer accumulator and a local variable for keeping a temporary copy of it.

You're right!  I updated my pull request.
See current output: https://gist.github.com/methane/185d75a3c8da762d85317dd95918a623

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue31415>
_______________________________________