Make some tests more frienly to MemoryError.
Free memory, unlock hanging threads.
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
index bde7ab6..753aa17 100644
--- a/Lib/test/test_itertools.py
+++ b/Lib/test/test_itertools.py
@@ -949,8 +949,12 @@
     # Issue 13454: Crash when deleting backward iterator from tee()
     def test_tee_del_backward(self):
         forward, backward = tee(repeat(None, 20000000))
-        any(forward)  # exhaust the iterator
-        del backward
+        try:
+            any(forward)  # exhaust the iterator
+            del backward
+        except:
+            del forward, backward
+            raise
 
     def test_StopIteration(self):
         self.assertRaises(StopIteration, izip().next)