SolrCloud should not compare commitTimeMSec to see if replicas are in sync

Today the replication code we compare if two replicas are in sync by checking the commit timestamp ( "commitTimeMSec" )

This made sense for master slave but I don't think is useful for SolrCloud since different replicas will commit at different times. We should not check for this in SolrCloud mode.

Ramkumar noted this on SOLR-7859 as well.