Rebroadcast Bug #290
Description
Our current flow of rebroadcasting finalize votes could cause a safety failure.
Say we finalize b3 which belongs to this chain of blocks. b1 <- b3(we have not yet finalized b1. However, our node has a notarization for b2. In our current logic, we would create a finalize vote for b2 and broadcast it. In fact a quorum of nodes had b2 notarized, but the block proposer build off the empty notarization in b2. We could end up creating a finalization for b2 which would be the same sequence as b3.