cpu_sim: Instructions in a packet are executed sequentially

[mrwright]

Example:

{ r0 <- 0 }
{ r0 <- 1; r1 <- r0 }

(encodes as 0xc0002000, 0xe0000000, 0xe0000000, 0xe0000000, 0xc0042000, 0xd4002020, 0xe0000000, 0xe0000000)
should leave r1 with the value 0, but will leave it with the value 1.

[gwillen]

Try now.