[issue18408] Fixes crashes found by pyfailmalloc

[Roundup Robot]

Roundup Robot added the comment:

New changeset de1ea7f84e08 by Victor Stinner in branch 'default':
Issue #18609, #18408: _ctypes_add_traceback() now clears the current exception
http://hg.python.org/cpython/rev/de1ea7f84e08

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