Fixed a critical bug in the runtime, where _d_allocmemoryT would mark the memory block as having pointers (for scanning) opposite of what it should. So pointers would not be seen and freed. Should fix a bunch of regressions with AAs.

module tangotests.switch2;

void main()
{
    int i=0;
    switch(i)
    {
    case 0:
        return;
    case 1:
        return;
    default:
        assert(0);
    }
}