Test LB+rel+CSEL2

AArch64 LB+rel+CSEL2
{
 0:X5=x; 0:X4=y;
 1:X4=y; 1:X5=x;
}
P0           | P1               ;
LDR W0,[X5]  | LDR W3,[X4]      ;
MOV W2,#1    | CMP W0,#1        ;
STLR W2,[X4] | CSEL W1,W1,W3,EQ ;
             | MOV W8,#7       ;
             | STR W8,[X5]     ;
Observed
    1:X3=1; 0:X0=7;