Fix test_spwd on OpenIndiana

Issue #18787: restore "bin" name in test_spwd but catch KeyError.

Author: vstinner

Lib/test/test_spwd.py

@@ -61,9 +61,14 @@ def test_getspnam(self):
 class TestSpwdNonRoot(unittest.TestCase):
 
     def test_getspnam_exception(self):
-        with self.assertRaises(PermissionError) as cm:
-            spwd.getspnam('root')
-        self.assertEqual(str(cm.exception), '[Errno 13] Permission denied')
+        name = 'bin'
+        try:
+            with self.assertRaises(PermissionError) as cm:
+                spwd.getspnam(name)
+        except KeyError as exc:
+            self.skipTest("spwd entry %r doesn't exist: %s" % (name, exc))
+        else:
+            self.assertEqual(str(cm.exception), '[Errno 13] Permission denied')
 
 
 if __name__ == "__main__":