I guess in CPython, __file__ will be the path to the pyc if that's how
the library was loaded.  (We don't do that but that difference isn't the
issue here.)  So that makes these tests, which print __file__, sensitive
to whether the last run of the test was through cpython (pyc exists and
__file__ ends in pyc) or through pyston (pyc exists but was wasn't valid
for cpython, and __file__ ends in py)

Just do some canonicalization when printing