Test ISA2+o-rel+acq-o+o-rb-o

LISA ISA2+o-rel+acq-o+o-rb-o
{
a = 1;
x = 2;
}
 P0             | P1              | P2;
 w[once] a 3    | r[acquire] r1 x | r[once] r3 c  ;
                |                 | f[rmb]        ;
 w[release] x 4 | w[once] c 1     | r[once] r2 a  ;
Observed
    2:r3=1; 2:r2=1; 1:r1=4;