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 bug66;
import std.stdio;
class Scene { string name() { return "Scene"; } }
class Group : Scene { this () { } }
void main() { writefln((new Group).name); }