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 aa5;

void main()
{
    int[int] aa;
    aa[42] = 1;
    int i = aa[42];
    assert(i == 1);
}