in itertools module (i.e. itertools.izip(), itertools.chain(), etc).

This was already done in Python3, but having it wrong leads to
incorrect debug output, so it seems worth fixing in 2.7 as well.

Patch by Victor Terrón.

Ezio.

Ezio.

#17526: fix an IndexError raised while passing code without filename to inspect.findsource().  Initial patch by Tyler Doyle.