test__api.py: ignore tests with socketpair on windows

greentest/test__api.py

@@ -62,6 +62,8 @@ class Test(greentest.TestCase):
         assert 'Invalid switch' in str(result), repr(str(result))
         switcher.kill()
 
+    if hasattr(socket, 'socketpair'):
+
         def _test_wait_read_invalid_switch(self, sleep):
             sock1, sock2 = socket.socketpair()
             try: