Windows Nanoserver images fail to build at the Official Image repo.

See this [PR](https://github.com/docker-library/official-images/pull/8781) for more details. The nanoserver Dockerfiles need to refactored to `COPY` the JDK / JRE dir from the `windowsservercore` or other regular images. Eg, see similar Dockerfile for [openjdk](https://github.com/docker-library/openjdk/blob/858926209579731ec66ac8d71b1d2ea24c4e8483/16/jdk/windows/nanoserver-1809/Dockerfile#L18)