Rolling back Privilege Cache to SimplePrivilegeCache does not work

The change in SENTRY-2539 uses TreePrivilegeCache as default implementation of privilege cache to improve authorization performance. However, rolling back to SimplePrivilegeCache does not work due to how Sentry creates the privilege cache.

The solution is to create the privilege cache based on configured class name and handle different constructor inputs properly. 

More test cases are added to verify that rollback works.