make/docs/NON_CORE_PKGS lists the package names of the non-core API
whose javadoc will be generated and included in the docs bundle.
com.oracle.net is not a non-core package and no javadoc is generated.
They should be removed from make/docs/NON_CORE_PKGS. Instead,
com.oracle.net should be included in generating ct.sym so that
the javac compiler will allow the use of this package.