DERBY-3476: Improve serialization logic for SystemPermission

Validate name and actions fields when deserializing a stored
SystemPermission, and throw an exception if the stored
SystemPermission is not a valid one.

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1608670 13f79535-47bb-0310-9956-ffa450edef68