Harvest template unit test should fail ZapiPerf templates that include a double caret counter

[cgrinds]

The test should fail when a zapi perf template contains

name:                     Spinhi
query:                    spinhi
object:                   spinhi

instance_key:             uuid

counters:
  - ^^instance_uuid  <=============== this is not supported in zapi perf
  - instance_name          => volume
  - node_name              => node
  - spinhi_fileops