bhyve(8): Minor cosmetic niceties in instemul failure

bhyve(8): Minor cosmetic niceties in instemul failure

Print the failed instruction stream as a contiguous stream of hex.  This
is closer to something you could throw at a disassembler than 0xHH 0xHH
0xHH.

Also, use the debug.h 'raw' stdio-aware printf helper to avoid the
cascading
         line
             effect.