NOTE: This method is internal/private to the Worker class. It has package access solely for testing.
This method relies on ShardInfo.equals() method returning true for ShardInfo objects which may have been
instantiated with parentShardIds in a different order (and rest of the fields being the equal). For example
shardInfo1.equals(shardInfo2) should return true with shardInfo1 and shardInfo2 defined as follows. ShardInfo
shardInfo1 = new ShardInfo(shardId1, concurrencyToken1, Arrays.asList("parent1", "parent2")); ShardInfo
shardInfo2 = new ShardInfo(shardId1, concurrencyToken1, Arrays.asList("parent2", "parent1"));