Disassembly should print "data16" prefix in Intel style

[derekbruening]

Maybe the recommended style changes and that's why we don't print "data16" in Intel style, yet xed now prints it?

From #8043:

$ for i in cf 9c 9d 60 61; do ~/dr/releases/DynamoRIO-Linux-11.91.20664/bin32/drdisas -syntax intel 66 $i; echo "foo 0x66 0x${i}" | ~/extsw/xed/obj/wkit/bin/xed -32 -F foo; done
 66 cf                iretw
                data16 iret
 66 9c                pushfw
                data16 pushf
 66 9d                popfw
                data16 popf
 66 60                pushaw
                data16 pusha
 66 61                popaw
                data16 popa