Fix some unittests for 64-bit asm. They were operating on int variables as if they were longs. This was causing asm1_1 to fail when compiled with -O3 because it was overwriting the spilled value of callee-saved register %rbx, which the runtime was using as a pointer value at the time.

struct V(T...) {
    T v;
}

alias V!(float, int) MyV;

void main()
{
    assert(MyV.sizeof == float.sizeof + int.sizeof);
    auto f = 3.75f;
    auto v = MyV(f, 3);
    assert(v.v[0] == 3.75f);
    assert(v.v[1] == 3);
}