Remove more statements from stats.sql
Some of the statements capturing stats reset timestamps have become
unnecessary after
a9a8108411e4, so let's remove them.
Author: Bharath Rupireddy
Discussion: https://postgr.es/m/CALj2ACUnvB_Yo=O1xApBa4CDqQpW-x=QM35GBN1MqVRAxAGXEg@mail.gmail.com