Test STRx+2LDSETptex+db+TLBI

AArch64 STRx+2LDSETptex+db+TLBI
TTHM=HA HD
{
pte_x=(db:0,dbm:1);
0:X2=x; 1:X2=x;
1:X4=pte_x;
}
  P0        | P1               ;
MOV W1,#1   | MOV X6,#1        ;
L0:         | LSL X6,X6,#7     ;
STR W1,[X2] | LDSET X6,X0,[X4] ; (* clear db atomically *)
            | DSB ISH          ;
            | LSR X9,X2,#12    ;
            | TLBI VAAE1IS,X9  ;
            | DSB ISH          ;
            | LDSET X6,X1,[X4] ; (* again *)
exists (1:X0=(oa:PA(x), dbm:1) /\ 1:X1=(oa:PA(x), dbm:1, db:0) /\ [PTE(x)]=(oa:PA(x), dbm:1) /\ [x]=1 /\ ~fault(P0:L0,x))