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 foreach4;
extern(C) int printf(char*, ...);
void main()
{
    int[] arr = new int[4];
    foreach(i,v;arr) {
        printf("arr[%u] = %d\n",i,v);
    }
}