Do not fetch a node index if we have a perfectly fine pointer already at hand.
Do not fetch a node index if we have a perfectly fine pointer already at hand.

[r22509]

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