I've seen the problem on Windows only. test_doctest fails and the
problem also causes test_gc to fail when it is run after test_doctest.
W/o a prior run of test_doctest test_gc doesn't fail.

File "c:\dev\python\py3k\lib\test\test_doctest.py", line 1570, in
test.test_doct
est.test_debug
Failed example:
    try: doctest.debug_src(s)
    finally: sys.stdin = real_stdin
Expected:
    > <string>(1)<module>()
    (Pdb) next
    12
    --Return--
    > <string>(1)<module>()->None
    (Pdb) print(x)
    12
    (Pdb) continue
Got:
    > c:\dev\python\py3k\lib\io.py(281)__del__()
    -> try:
    (Pdb) next
    > c:\dev\python\py3k\lib\io.py(282)__del__()
    -> self.close()
    (Pdb) print(x)
    *** NameError: NameError("name 'x' is not defined",)
    (Pdb) continue
    12
**********************************************************************
1 items had failures:
   1 of   4 in test.test_doctest.test_debug
***Test Failed*** 1 failures.
test test_doctest failed -- 1 of 418 doctests failed
test_gc
test test_gc failed -- Traceback (most recent call last):
  File "c:\dev\python\py3k\lib\test\test_gc.py", line 193, in test_saveall
    self.assertEqual(gc.garbage, [])
AssertionError: [<io.BytesIO object at 0x01237968>] != []

2 tests failed:
    test_doctest test_gc