fix PR8686, accepting a 'b' suffix at the end of all the setcc

instructions.  I choose to handle this with an asmparser hack,
though it could be handled by changing all the instruction definitions
to allow be "setneb" instead of "setne".  The asm parser hack is
better in this case, because we want the disassembler to produce
setne, not setneb.

llvm-svn: 120260