Fix for  4165 : Replica can be slow to replay changes when using large window size

When checking dependencies during replay of operations on the consumer
the replication go through the list of pending changes while holding the
pending changes lock.
When using large values for the window size, the list can be large
and this can therefore cause large replication delay on the replica. 

The solution is to limit the parsing to the list of changes that are older than the current change.