ZTS: Fix in-tree dbufstats test case
Commit a887d653 updated the dbufstats such that escalated privileges
are required. Since all tests under cli_user are run with normal
privileges move this test case to a location where it will be run
required privileges.
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9118
Closes #9196