bpf: simplify disasm state machine.

The code ends up slightly longer, but the decoding is more consistent from
one instruction class to another, so hopefully it's easier to make sense of it.

Change-Id: Ia22c2ebb0865536da0c3dac6876bdb0b20075f04
Reviewed-on: https://go-review.googlesource.com/21215
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2 files changed