Test MP-swp

AArch64 MP-swp

{
0:X1=x; 0:X3=y;
1:X1=x; 1:X3=y; 1:X5=z;
}
 P0           |  P1                 ;
 MOV W0,#1    | LDR W0,[X3]         ;
 STR W0,[X1]  | SWP W0,W2,[X5]      ;
 MOV W2,#1    | AND W4,W2,#2        ;
 STLR W2,[X3] | LDR W6,[X1,W4,SXTW] ;
Observed
    1:X6=0; 1:X0=1;