Test MP+dmb+rs

Run MP+dmb+rs in model, using armmem

ARM MP+dmb+rs
"register shadowing that works"
Prefetch=1:x=T
{
%x0=x; %y0=y;
%y1=y; %x1=x;
}
 P0            | P1            ;
 MOV R0, #1    | LDR R1, [%y1] ;
 STR R0, [%x0] | MOV R0,R1     ;
 DMB           | LDR R1, [%x1] ;
 MOV R1, #1    |               ;
 STR R1, [%y0] |               ;
exists
(1:R0=1 /\ 1:R1=0)