Don't trigger BJ_ASSERT(false) on invalid BPF_Jxxx opcode in jmp_to_op().
Don't trigger BJ_ASSERT(false) on invalid BPF_Jxxx opcode in jmp_to_op().

This change helps survive AFL fuzzing without calling bpf_validate() first.

Also change alu_to_op() function to have a similar interface.

alnsn/bpfjit