AMD64 Windows10 3.x, build 856:
https://buildbot.python.org/all/#/builders/146/builds/856

17 tests failed:
    test_exceptions test_fileio test_io test_isinstance test_json
    test_lib2to3 test_logging test_pickle test_pickletools
    test_plistlib test_richcmp test_runpy test_sys test_threading
    test_traceback test_typing test_xml_etree

It may be a regression caused by:
"bpo-43166: Disable ceval.c optimisations for Windows debug builds (GH-24485)"
https://github.com/python/cpython/commit/b74396c3167cc780f01309148db02709bc37b432

The latest successful build was 11 days ago (Feb 9):
https://buildbot.python.org/all/#/builders/146/builds/819

----

0:01:46 load avg: 14.25 [ 61/426/1] test_xml_etree crashed (Exit code 3221225725) -- running: test_tokenize (46.4 sec), test_largefile (1 min 10 sec)
Windows fatal exception: stack overflow

Current thread 0x0000110c (most recent call first):
  File "D:\buildarea\3.x.bolen-windows10\build\lib\xml\etree\ElementTree.py", line 178 in __repr__
  File "D:\buildarea\3.x.bolen-windows10\build\lib\xml\etree\ElementTree.py", line 178 in __repr__
  File "D:\buildarea\3.x.bolen-windows10\build\lib\xml\etree\ElementTree.py", line 178 in __repr__
  ...

======================================================================
FAIL: test_recursion_limit (test.test_threading.ThreadingExceptionTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\buildarea\3.x.bolen-windows10\build\lib\test\test_threading.py", line 1203, in test_recursion_limit
    self.assertEqual(p.returncode, 0, "Unexpected error: " + stderr.decode())
AssertionError: 3221225725 != 0 : Unexpected error: 

0:05:09 load avg: 29.65 [140/426/3] test_traceback crashed (Exit code 3221225725) -- running: test_concurrent_futures (2 min 6 sec), test_mmap (2 min)
Windows fatal exception: stack overflow

Current thread 0x00000118 (most recent call first):
  File "D:\buildarea\3.x.bolen-windows10\build\lib\test\test_traceback.py", line 1154 in f
  File "D:\buildarea\3.x.bolen-windows10\build\lib\test\test_traceback.py", line 1156 in f
  File "D:\buildarea\3.x.bolen-windows10\build\lib\test\test_traceback.py", line 1156 in f
  ...

0:06:14 load avg: 29.15 [151/426/4] test_lib2to3 crashed (Exit code 3221225725) -- running: test_multiprocessing_spawn (31.7 sec), test_capi (1 min 3 sec), test_mmap (3 min 4 sec)
Windows fatal exception: stack overflow

Current thread 0x00001b90 (most recent call first):
  File "D:\buildarea\3.x.bolen-windows10\build\lib\lib2to3\pytree.py", line 496 in generate_matches
  File "D:\buildarea\3.x.bolen-windows10\build\lib\lib2to3\pytree.py", line 845 in generate_matches
  ...