- do not combine blocks if both have a label
- do not combine blocks if both have a label

[r24449]

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