Still print this, but use py2/py3 compat syntax

I realised being able to print is probably an essential part of this
test which I may have inadvertendly disabled, so correct that.

testing/test_junitxml.py

@@ -295,7 +295,7 @@ class TestPython:
                 assert M1 == M2
             """)
         result, dom = runandparse(testdir)
-        # print dom.toxml()
+        print(dom.toxml())
 
     def test_pass_captures_stdout(self, testdir):
         testdir.makepyfile("""