Test C11-A

AArch64 C11-A
"Example A from notes41"
{
0:X1=x;
1:X1=x; 1:X3=y;
2:X1=y;
3:X1=y; 3:X3=x;
}
 P0           | P1           | P2           | P3           ;
 MOV W0,#1    | LDAR W0,[X1] | MOV W0,#1    | LDAR W0,[X1] ;
 STLR W0,[X1] | LDAR W2,[X3] | STLR W0,[X1] | LDAR W2,[X3] ;
 MOV W2,#2    |              | MOV W2,#2    |              ;
 STR W2,[X1]  |              | STR W2,[X1]  |              ;
exists
(x=2 /\ y=2 /\ 1:X0=2 /\ 1:X2=0 /\ 3:X0=2 /\ 3:X2=0)