builtin_map(): A better fix for the previous leak plug (remember PyList_Append steals a reference even if it fails).
builtin_map(): A better fix for the previous leak plug (remember
PyList_Append steals a reference even if it fails).

builtin_filter(): Had the same leak problem as builtin_map().

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator