[Toy build testing] Mutation queue grows unbounded after indexer restart.

Mutation queue grows unbounded after indexer restart.

Steps to reproduce:
1)Load 20M items and create and build 2i index on a single field.
2)Wait for index ready and restart indexer. start KV workload of 12.5K sets(updates) per sec.
3)observe from server stats that mutation queue size keeps growing and doesn't come down.