In all cases where aliens have purchased real estate within this Commonwealth, and have sold the same, the said sales shall be valid, to all intents and purposes, and shall be construed to vest the title to the said real estate, as fully and effectually as if the said aliens had been citizens at the time of purchasing the same and in all cases where any alien residing in this Commonwealth, shall have purchased or held real estate therein, and shall have died without having been naturalized, the title thereof is hereby confirmed to his heirs, who, in case he had been a citizen would have inherited the same, and there shall be no escheat by reason of such alienage: Provided, That nothing herein contained shall in any wise affect or impair the vested rights of any other individual or individuals.