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 bug52;
struct Vec { double x,y,z; }
struct Pair(T, U) { T first; U second; }
typedef Pair!(double, Vec) Hit;
void main() {}