Add a mocknet test that for a duration of time randomly restarts all the nodes

[SkidanovAlex]

Add a mocknet test for for a duration of time randomly restarts all the nodes.
We want to test that we can continue operating if
a) For some time no node is alive, and
b) Nodes get restarted multiple times in a row without getting a chance to fully sync

[stale]

This issue has been automatically marked as stale because it has not had recent activity in the last 2 months.
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[stale]

This issue has been automatically marked as stale because it has not had recent activity in the last 2 months.
It will be closed in 7 days if no further activity occurs.
Thank you for your contributions.