Test 2+2W+xp+dmb

AArch64 2+2W+xp+dmb
Prefetch=0:x=F,0:y=W,1:y=F,1:x=W
Com=Ws Ws
Orig=PodWWXP Wse DMB.SYdWW WsePX
{
0:X0=x; 0:X5=y;
1:X1=y; 1:X3=x;
}
 P0                  | P1          ;
 MOV W1,#2           | MOV W0,#2   ;
 LDXR W2,[X0]        | STR W0,[X1] ;
 STXR W3,W1,[X0]     | DMB SY      ;
 MOV W4,#1           | MOV W2,#1   ;
 STR W4,[X5]         | STR W2,[X3] ;
Observed
    y=2; x=1; 0:X3=1; 0:X2=1;
and y=2; x=2; 0:X3=0; 0:X2=1;