Test CO-MP+sync+po

PPC CO-MP+sync+po

{0:r2=x; 1:r2=x;}

 P0          | P1           ;
 li  r0,1    | lwz r0,0(r2) ;
 stw r0,0(r2)| lwz r1,0(r2) ;
 sync        |              ;
 li  r1,2    |              ;
 stw r1,0(r2)|              ;
exists (1:r0=2 /\ 1:r1=1 \/ 1:r0=2 /\ 1:r1=0 \/ 1:r0=1 /\ 1:r1=0)