Tests in JunitXmlPluginFunctionalFailureTest fail on Windows

Execute functional tests in `test_junitxml_plugin.py:JunitXmlPluginFunctionalFailureTest` on Windows. Tests fail (Windows uses different line separator):
```
D:\src\nose2\nose2\tests\functional>nosetests --nologcapture test_junitxml_plugin.py:JunitXmlPluginFunctionalFailureTest
FFF
======================================================================
FAIL: test_failure_to_read_empty_properties (nose2.tests.functional.test_junitxml_plugin.JunitXmlPluginFunctionalFailureTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\src\nose2\nose2\tests\functional\test_junitxml_plugin.py", line 150, in test_failure_to_read_empty_properties
    proc, stderr=r'Internal Error: runTests aborted: JUnitXML: could not decode file: \'.*/empty_properties/properties\.json\'')
  File "D:\src\nose2\nose2\tests\_common.py", line 64, in assertTestRunOutputMatches
    testf(util.safe_decode(cmd_stderr), stderr)
AssertionError: Regexp didn't match: "Internal Error: runTests aborted: JUnitXML: could not decode file: \\'.*/empty_properties/properties\\.json\\'" not found in u"test (test_junitxml_
empty_properties.Test) ... ok\nInternal Error: runTests aborted: JUnitXML: could not decode file: 'D:\\src\\nose2\\nose2\\tests\\functional\\support\\scenario\\junitxml\\empty_propertie
s\\properties.json'\n"

======================================================================
FAIL: test_failure_to_read_missing_properties (nose2.tests.functional.test_junitxml_plugin.JunitXmlPluginFunctionalFailureTest)
----------------------------------------------------------------------
...
======================================================================
FAIL: test_failure_to_write_report (nose2.tests.functional.test_junitxml_plugin.JunitXmlPluginFunctionalFailureTest)
----------------------------------------------------------------------
...
----------------------------------------------------------------------
Ran 3 tests in 0.102s

FAILED (failures=3)

```