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 union2;

union U
{
    float f;
    long l;
}

U u;

void main()
{
    assert(u.f !<>= 0);
    {
        uint* p = 1 + cast(uint*)&u;
        {assert(*p == 0);}
    }
}