Create regression TestCrossOnSameSimulatorNoRootDestPerm() to check that avatars are not allowed to cross into a neighbour where they are not authorized, even if a child agent was allowed.
Revert "Also check user authorization if looking to upgrade from a child to a root agent."

This reverts commit c7ded0618c303f8c24a91c83c2129292beebe466.
This proves not to be necessary - the necessary checks are already being done via QueryAccess() before cross or teleport