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 typeinfo5;

void main()
{
    enum E : uint {
        A,B,C
    }
    auto ti = typeid(E);
    assert(ti.next() is typeid(uint));
    assert(ti.init is null);
}