bearch: When dumping backend info, do not print an error, when a node has no in_reqs, if its arity is 0.
bearch: When dumping backend info, do not print an error, when a node has no in_reqs, if its arity is 0.

libfirm/libfirm,libfirm/libfirm,MatzeB/libfirm,MatzeB/libfirm,jonashaag/libfirm,MatzeB/libfirm,jonashaag/libfirm,davidgiven/libfirm,8l/libfirm,davidgiven/libfirm,killbug2004/libfirm,davidgiven/libfirm,jonashaag/libfirm,killbug2004/libfirm,davidgiven/libfirm,8l/libfirm,MatzeB/libfirm,8l/libfirm,libfirm/libfirm,8l/libfirm,killbug2004/libfirm,davidgiven/libfirm,libfirm/libfirm,jonashaag/libfirm,8l/libfirm,jonashaag/libfirm,killbug2004/libfirm,killbug2004/libfirm,libfirm/libfirm,davidgiven/libfirm,MatzeB/libfirm,killbug2004/libfirm,MatzeB/libfirm,8l/libfirm,davidgiven/libfirm,jonashaag/libfirm,killbug2004/libfirm,8l/libfirm,jonashaag/libfirm,MatzeB/libfirm