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 structinit2;

struct Imp
{
    int i;
    long l;
    float f;
}

void main()
{
    Imp i;
    assert(i.i == 0);
    assert(i.l == 0L);
    assert(i.f !<>= 0.0f);
}