regression test: flagging nodes in the connectivity tracker during an epoch switch

[SurfingNerd]

on Alpha4 we had problems if a validator gets flagged during the key generation phase,
this has lead to a scenario with an epoch switch without a proper key written.

we should never do an epoch switch if we do not have generated a complete key.
It results in a validator set that does not have a shared key to generate/validate blocks

?! could also be an end to end test ?!

[SurfingNerd]

testing: behaviour should be better now.
but we wont develop a regression unit test, we will develop a regression end-to-end test in diamond-dev-tools