In list_emit we walk over listerr_head freeing the list,
but the head pointer remain carrying old value. Need
to clean it up once traverse is done to not access
already freed memory later.
https://bugzilla.nasm.us/show_bug.cgi?id=3392538
Reported-by: russvz@comcast.net
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>