Rebalance out taking more than 16 hrs

Build: 7.1.0-1300
Test: -test tests/fts/cheshire-cat/test_fts_clusterops_cheshire_cat_coll_crud_freetier.yml -scope tests/fts/cheshire-cat/scope_fts_cheshire_cat_free_tier.yml

• Cluster with 3 nodes having kv,n1ql, search, index on all the nodes
• Create 1 bucket, 100 scopes and 50 collections in each scopes
• Created 500 indexes: one index (1 partition) on each collection
• Create 2500 GSI indexes ( 5 on each collection)
• Load documents on some of the collections
• Run fts query workload
• Kill fts on 172.23.106.242 and wait for 25 mins
• Rebalance in 172.23.107.89 with fts service
• Rebalance failed due OOM kill of fts node on 172.23.106.242
• Kill fts on 172.23.106.243 and wait for 15 mins
• Mutate and add some more docs
• rebalance out 172.23.106.242

Rebalance taking more than 16hrs and continuing.

Logs:

url : https://cb-jira.s3.us-east-2.amazonaws.com/logs/systestmon-1631977995/collectinfo-2021-09-18T151316-ns_1%40172.23.106.242.zip
url : https://cb-jira.s3.us-east-2.amazonaws.com/logs/systestmon-1631977995/collectinfo-2021-09-18T151316-ns_1%40172.23.106.243.zip
url : https://cb-jira.s3.us-east-2.amazonaws.com/logs/systestmon-1631977995/collectinfo-2021-09-18T151316-ns_1%40172.23.106.253.zip
url : https://cb-jira.s3.us-east-2.amazonaws.com/logs/systestmon-1631977995/collectinfo-2021-09-18T151316-ns_1%40172.23.107.89.zip