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 bug74;

char[] sformat(char[] s, ...)
{
    TypeInfo[] ti = _arguments;
    void* args = _argptr;
    return "";
}

void main()
{
}