remove tf_lowered_type flag when cloning method types (not sure if that is the correct fix)
remove tf_lowered_type flag when cloning method types (not sure if that is the correct fix)

[r17757]

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