Fix the sceSas tests, add some checks to them

Doesn't test all that much, but demonstrates testability.

Also made some rash assumptions about the structure of the SasCore struct based on what it writes to memory.

I was happy when I got it to work, but I think the actual problem was the thread priority, which is weird since it doesn't seem to reschedule.... not sure, but it doesn't lock up my PSP anymore.

I wonder what a negative volume means... I guess it makes sense.

-[Unknown]