Add a mocknet test that tests the behavior of the cluster under some simple adversarial conditions

[SkidanovAlex]

(a) creating large numbers of blocks per height and sending them to all the nodes;
(c) spamming with state sync requests;
(d) spamming with account announces;
(e) spamming with NetworkRequest::Sync requests.

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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.

[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.