Patch by Guilherme.

before, only attempt the import where nt._getfinalpathname could actually
work, i.e., Windows Vista and beyond.

it for now until a buildbot-safe solution comes up.

ntpath.sameopenfile.

this was causing reversed method calls like float.__radd__(3.0, 1) to
return NotImplemented instead of the expected numeric value.

The test is semi-dumb, it just makes sure something comes back since we
don't have a solid source to validate the returned login. We can't be 100%
sure that the USERNAME env var will always match what os.getlogin() returns,
so we don't make any specific assertion there.

objects explicitly instead of letting them linger on.

Patch by Florian Festi.

TestSkip exception.