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 bug44;

struct rgb
{
    long l;
}

void foo()
{
}

rgb test() {
  scope(exit) foo();
  return rgb();
}

void main()
{
    rgb r = test();
}