move convenience property groups out of ir_graph_properties enum
move convenience property groups out of ir_graph_properties enum

This doesn't change anything, but let's gdb print ir_graph_properties
variables/member in a nicer way.

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