WL#13706: Increase default group_replication_autorejoin_tries

Affects: Server-8.0   —   Status: Complete

Change the default group_replication_autorejoin_tries from 0 to (for example) 3.

Currently, group_replication_autorejoin_tries is set to 0, which means it is 

With this setting, a group replication network partition for longer than 5 seconds 
causes the member to exit the group and not come back, which results in the need 
to do a manual operation to bring the member back.

The goal is to provide 'automatic network partition handling', including 
recovering from network partitions, which is most effectively achieved by setting  
group_replication_autorejoin_tries > 0

FR1: The default value of the variable group_replication_autorejoin_tries shall be 
set to 3.

FR2: It shall be possible to set group_replication_autorejoin_tries to a valid 
value other than 3.
Change the default value of group_replication_autorejoin_tries from '0' to '3'.

Current MTR regressions will run with the new default and shall test the changed 

Evaluate the list of MTR/JET tests failing. Check if these are expected due to the 
change in autorejoin retries and set the group_replication_autorejoin_tries to 
zero for such testcases.