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.

module tangotests.mem5;

class SC
{
    int* ip;
    this()
    {
        ip = new int;
    }
    ~this()
    {
        delete ip;
    }
    void check()
    {
        assert(ip !is null);
    }
}

void main()
{
    scope sc = new SC;
    sc.check();
}