Issue #18408: PyEval_EvalFrameEx() and PyEval_CallObjectWithKeywords() now fail with an assertion error if they are called with an exception set (PyErr_Occurred()). If these functions are called with an exception set, the exception may be cleared and so the caller looses its exception. Add also assertions to PyEval_CallObjectWithKeywords() and call_function() to check if the function succeed with no exception set, or the function failed with an exception set.