Simplify x87 sim_Return().
Simplify x87 sim_Return().

Just flush the fp stack, only check for the correct number of fp values in debug builds.

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