x86: disassembling over-long insns
The present way of dealing with them - misusing MAX_MNEM_SIZE, which has
nothing to do with insn length - leads to inconsistent results. Since we
allow for up to MAX_CODE_LENGTH - 1 prefix bytes (which then could be
followed by another MAX_CODE_LENGTH "normal" insn bytes until we're done
decoding), size the_buffer[] accordingly.
Move struct dis_private down to be able to use MAX_CODE_LENGTH without
moving its #define. While doing this also alter the order to have the
potentially large array last.