(Merge 3.4) Issue python#25274: test_recursionlimit_recovery() of tes…

…t_sys now checks

sys.gettrace() when the test is executed, not when the module is loaded.

sys.settrace() may be after after the test is loaded.

Lib/test/test_sys.py

@@ -197,9 +197,10 @@ def test_recursionlimit(self):
         self.assertEqual(sys.getrecursionlimit(), 10000)
         sys.setrecursionlimit(oldlimit)
 
-    @unittest.skipIf(hasattr(sys, 'gettrace') and sys.gettrace(),
-                     'fatal error if run with a trace function')
     def test_recursionlimit_recovery(self):
+        if hasattr(sys, 'gettrace') and sys.gettrace():
+            self.skipTest('fatal error if run with a trace function')
+
         # NOTE: this test is slightly fragile in that it depends on the current
         # recursion count when executing the test being low enough so as to
         # trigger the recursion recovery detection in the _Py_MakeEndRecCheck