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.sync3;

void main()
{
    int i = foo();
}

int foo()
{
    int res;
    synchronized
    {
        scope(exit) res--;
        res++;
        return res;
    }
}