The UBsan buildbot is failing test_faulthandler. We should either spread some __attribute__((no_sanitize_undefined)) around or make the tests skip.

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FAIL: test_enable_fd (test.test_faulthandler.FaultHandlerTests)
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Traceback (most recent call last):
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 274, in test_enable_fd
    self.check_fatal_error("""
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 115, in check_fatal_error
    self.check_error(code, line_number, fatal_error, **kw)
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 108, in check_error
    output, exitcode = self.get_output(code, filename=filename, fd=fd)
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 73, in get_output
    self.assertEqual(output, '')
AssertionError: 'UndefinedBehaviorSanitizer:DEADLYSIGNAL\n[2619 chars]TING' != ''
Diff is 2693 characters long. Set self.maxDiff to None to see it.
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FAIL: test_enable_file (test.test_faulthandler.FaultHandlerTests)
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Traceback (most recent call last):
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 258, in test_enable_file
    self.check_fatal_error("""
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 115, in check_fatal_error
    self.check_error(code, line_number, fatal_error, **kw)
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 108, in check_error
    output, exitcode = self.get_output(code, filename=filename, fd=fd)
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 68, in get_output
    self.assertEqual(output, '')
AssertionError: 'UndefinedBehaviorSanitizer:DEADLYSIGNAL\n[2619 chars]TING' != ''
Diff is 2693 characters long. Set self.maxDiff to None to see it.
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FAIL: test_sigfpe (test.test_faulthandler.FaultHandlerTests)
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Traceback (most recent call last):
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 176, in test_sigfpe
    self.check_fatal_error("""
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 115, in check_fatal_error
    self.check_error(code, line_number, fatal_error, **kw)
  File "/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Lib/test/test_faulthandler.py", line 110, in check_error
    self.assertRegex(output, regex)
AssertionError: Regex didn't match: '^Fatal Python error: Floating point exception\n\nCurrent thread 0x[0-9a-f]+ \\(most recent call first\\):\n  File "<string>", line 3 in <module>' not found in 'Modules/faulthandler.c:1059:11: runtime error: division by zero\nFatal Python error: Floating point exception\n\nCurrent thread 0x00007f14c5e81740 (most recent call first):\n  File "<string>", line 3 in <module>\nUndefinedBehaviorSanitizer:DEADLYSIGNAL\n==5027==ERROR: UndefinedBehaviorSanitizer: FPE on unknown address 0x006d000013a3 (pc 0x7f14c5355f9f bp 0x000002f485a0 sp 0x000002f698e8 T5027)\n    #0 0x7f14c5355f9e in gsignal (/lib/x86_64-linux-gnu/libpthread.so.0+0x10f9e)\n    #1 0x7f14c53560bf  (/lib/x86_64-linux-gnu/libpthread.so.0+0x110bf)\n    #2 0x829906 in faulthandler_sigfpe /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/./Modules/faulthandler.c:1059:11\n    #3 0x4707c3 in _PyMethodDef_RawFastCallKeywords /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Objects/call.c\n    #4 0x46e5d1 in _PyCFunction_FastCallKeywords /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Objects/call.c:730:14\n    #5 0x656805 in call_function /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Python/ceval.c:4570:9\n    #6 0x64b0d6 in _PyEval_EvalFrameDefault /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Python/ceval.c:3164:23\n    #7 0x6596be in _PyEval_EvalCodeWithName /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Python/ceval.c:3946:14\n    #8 0x6384ee in PyEval_EvalCodeEx /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Python/ceval.c:3975:12\n    #9 0x6384ee in PyEval_EvalCode /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Python/ceval.c:508\n    #10 0x6e816e in run_mod /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Python/pythonrun.c:1030:9\n    #11 0x6e816e in PyRun_StringFlags /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Python/pythonrun.c:954\n    #12 0x6e80bc in PyRun_SimpleStringFlags /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Python/pythonrun.c:450:9\n    #13 0x44db44 in pymain_run_command /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Modules/main.c:293:11\n    #14 0x44db44 in pymain_run_python /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Modules/main.c:1600\n    #15 0x44db44 in pymain_main /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Modules/main.c:1758\n    #16 0x44f29b in _Py_UnixMain /var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/Modules/main.c:1795:12\n    #17 0x7f14c4ba72e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)\n    #18 0x425499 in _start (/var/lib/buildbot/clang-ubsan/3.x.gps-clang-ubsan/build/python+0x425499)\n\nUndefinedBehaviorSanitizer can not provide additional info.\n==5027==ABORTING'
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