[2.7] bpo-30442: Skips refcount test in test_xml_etree under coverage (GH-1767) (#3549)

(cherry picked from commit 1de4705d00168afa8c5b6741af02e21fc609af58)
diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
index 60b26ea..55d7010 100644
--- a/Lib/test/test_xml_etree.py
+++ b/Lib/test/test_xml_etree.py
@@ -1338,6 +1338,7 @@
         self.assertEqual(t.find('.//paragraph').text,
             u'A new cultivar of Begonia plant named \u2018BCT9801BEG\u2019.')
 
+    @unittest.skipIf(sys.gettrace(), "Skips under coverage.")
     def test_bug_xmltoolkit63(self):
         # Check reference leak.
         def xmltoolkit63():