Test LB+poxp+poxx+SYS2

AArch64 LB+poxp+poxx+SYS2
"PodRWXP RfePX PodRWXX RfeXX"
Cycle=RfePX PodRWXX RfeXX PodRWXP
Relax=RfePX RfeXX
Safe=PodRW
Prefetch=0:x=F,0:y=W,1:y=F,1:x=W
Com=Rf Rf
Orig=PodRWXP RfePX PodRWXX RfeXX
{
0:X0=x; 0:X4=y;
1:X0=y; 1:X3=x;
}
 P0              | P1              ;
 LDXR W1,[X0]    | LDXR W1,[X0]    ;
 STXR W2,W1,[X0] | STXR W2,W1,[X0] ;
 MOV W3,#1       | MOV W4,#1       ;
 STR W3,[X4]     | LDXR W5,[X3]    ;
                 | STXR W6,W4,[X3] ;
Observed
    y=1; x=1; 1:X6=0; 1:X5=0; 1:X2=1; 1:X1=1; 0:X2=1; 0:X1=1;
and y=1; x=1; 1:X6=0; 1:X5=0; 1:X2=0; 1:X1=1; 0:X2=1; 0:X1=1;
and y=1; x=1; 1:X6=0; 1:X5=0; 1:X2=1; 1:X1=1; 0:X2=0; 0:X1=1;
and y=1; x=1; 1:X6=0; 1:X5=0; 1:X2=0; 1:X1=1; 0:X2=0; 0:X1=1;