Approving the behaviour on 3.6.5 and fresh cpython-built @master:

From the docs: test_sundry "contains extremely basic regression tests... which don't have separate tests of their own".

IMHO 2to3 can be added to the whitelist of test_sundry as it comes with its own unit tests. When test_sundry runs import_tool with '2to3', lib2to3 is called without args, resulting in an exit 2 which breaks the basic test.