Test CASAL+FAIL

AArch64 CASAL+FAIL
Variant=skip
{
int x;
int y;
0:X1=(oa:PA(x),db:0);
0:X2=y; 0:X4=PTE(x);
1:X2=y; 1:X4=x;
}

  P0         | P1               ;
 MOV W3,#1   | MOV W1,#0        ;
 STR W3,[X2] | MOV W3,#1        ;
 DSB ISH     |L0:               ;
 STR X1,[X4] | CASAL W1,w3,[X4] ;
             | LDR W5,[X2]      ;
exists (1:X5=0 /\ fault(P1:L0,x,MMU:Permission))