Large nopsleds make it easier for ROP machinery to sloppily reach targets.

Large nopsleds make it easier for ROP machinery to sloppily reach targets.
Convert these to "trapsleds' instead.  Since these can occur inside
fall-through blocks of code (and gcc sure isn't helping us by identifying
those), convert most to "short jump over" followed a sequence of int3.
This works for sled sizes 3-15, for i386 and amd64.   Work by Todd Mortimer
ok mlarkin