Yes, you can do that, but why bother? You can start your 2019 tax return next year without transferring information from 2018, and enter information from your 2018 tax return as needed. If TurboTax needs information from your 2019 tax return it will ask for it. It's probably a lot more work to create a complete dummy 2018 tax return than to just enter the necessary information next year.

If you do decide to create a dummy 2018 return, it's your responsibility to make sure that it exactly matches the 2018 tax return that you filed, and to check the information that transfers to your 2019 tax return next year to make sure it's accurate.