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 bug45;

void foo() {
    int bar;
    scope(exit) { bar++; }
    if (bar) return;
}

void main() {
    foo();
}