RANGER-5131: remove finalize from policy engine

[vyommani]

What changes were proposed in this pull request?

Removal of finalize() method from PolicyEngine class

As part of our efforts to ensure compatibility with future JDK versions, this code change removes the deprecated finalize() method from the PolicyEngine class. The finalize() method has been deprecated since JDK 9 and is slated for removal in future JDK versions.

Impact Analysis

A thorough analysis was conducted to assess the impact of removing the finalize() method. The results indicate that there is no adverse impact on the functionality of the PolicyEngine class.

Existing Cleanup Mechanisms

It's worth noting that we already have a cleanup() method in the RangerBasePlugin class, which allows users to release resources held by the PolicyEngine. This method provides a manual way to perform cleanup operations, ensuring that resources are properly released when needed.

How was this patch tested?

mvn clean install