Test R+fence.w.w+fence.tso

RISCV R+fence.w.w+fence.tso
"based on: Fence.w.wdWW Wse Fence.rw.rwdWR Fre"
{
0:x6=x; 0:x8=y;
1:x6=y; 1:x8=x;
}
 P0          | P1          ;
 ori x5,x0,1 | ori x5,x0,2 ;
 sw x5,0(x6) | sw x5,0(x6) ;
 fence w,w   | fence.tso   ;
 ori x7,x0,1 | lw x7,0(x8) ;
 sw x7,0(x8) |             ;
exists
(y=2 /\ 1:x7=0)