Test R+dmb.sy+addrxp

AArch64 R+dmb.sy+addrxp
"based on: DMB.SYdWW WsePX PosWRXP DpAddrdR Fre"
Prefetch=0:x=F,0:y=W,1:y=F,1:x=T
Com=Ws Fr
{ ok=1;
0:X1=x; 0:X3=y;
1:X0=y; 1:X7=x;
}
 P0          | P1                  ;
 MOV W0,#1   | MOV W1,#2           ;
 STR W0,[X1] | LDXR W2,[X0]        ;
 DMB SY      | STXR W3,W1,[X0]     ;
 MOV W2,#1   | EOR W5,W3,W3        ;
 STR W2,[X3] | LDR W6,[X7,W5,SXTW] ;
Observed
    y=2; 1:X6=0; 1:X3=0; 1:X2=1;