Just try to open files from the ZIP for reading, don't extract them to avoid
UnicodeEncodeError if the filename is not encodable to the filesystem encoding
(e.g. ASCII locale encoding).

The tests now pass all combinations of -O/-OO and -B.  See also #7071
and #6292 for previous variations on the same theme.

test_versionpredicate needs a skip when sys.flags.optimize is true, but
I don’t know how to make that work with a DocTestSuite.

Patch by Mher Movsisyan.

Mac OS X and FreeBSD to reduce the chances of a crash instead of a
"maximum recursion depth" RuntimeError exception.
(patch by Ronald Oussoren)

the file is closed.

their encode() method anymore, but continue to call the reset() method if the
final argument is True.

to be able to unload the module.