[system test] Indexes seem to be rebuilding post reboot on a indexed cluster

1. Last 2 phases on the System testing.

• Reboot entire cluster.

Couple of observations

• indexes on bucket default ( active and replica indexes) seem to be rebuilt.
  example: index fare_idx,
  items remaining on index pre reboot:0
  post reboot: 10M

likewise for every index for bucket default.

• Additionally, the index active resident ratio drops from 50-60% to 20-25%
  Unlike KV where the access logs/ last accessed infromation is used to maximize active KV resident ratio.

attached screenshot of the cluster before/after reboot
attached logs from node 233, index node for default

attaching logs from all nodes.