arc_summary: consolidate test case

arc_summary: consolidate test case

Since we're only installing one version of arc_summary we only
need one test case.  Update the test to determine which version
is available and then test its supported flags.

Remove files for misc tests which should have been cleaned up.

Reviewed-by: John Ramsden <johnramsden@riseup.net>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8096