Reruns TestLoadIncrementalHFiles using LoadIncrementalHFiles in secure mode.
This suite is unable to verify the security handoff/turnover
as miniCluster is running as system user thus has root privileges
and delegation tokens don't seem to work on miniDFS.
Thus SecureBulkload can only be completely verified by running
integration tests against a secure cluster. This suite is still
invaluable as it verifies the other mechanisms that need to be
supported as part of a LoadIncrementalFiles call.