Test LB+po+poxp+SYS2

AArch64 LB+po+poxp+SYS2
"PodRW RfePX PodRWXP Rfe"
Cycle=Rfe PodRW RfePX PodRWXP
Relax=RfePX
Safe=Rfe PodRW
Prefetch=0:x=F,0:y=W,1:y=F,1:x=W
Com=Rf Rf
Orig=PodRW RfePX PodRWXP Rfe
{
0:X1=x; 0:X3=y;
1:X0=y; 1:X4=x;
}
 P0          | P1              ;
 LDR W0,[X1] | LDXR W1,[X0]    ;
 MOV W2,#1   | STXR W2,W1,[X0] ;
 STR W2,[X3] | MOV W3,#1       ;
             | STR W3,[X4]     ;
Observed
    y=1; 1:X2=1; 1:X1=1; 0:X0=1;