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 bug20;
extern(C) int printf(char*, ...);

void func(void delegate() dg)
{
    dg();
}

void main()
{
    int i = 42;
    void delegate() dg = {
        i++;
    };
    printf("i = %d\n",i);
    func(dg);
    printf("i = %d\n",i);
    assert(i == 43);
}