BFT synchronizer: integration test against an orderer that does block censorship

[tock-ibm]

• Run a 4 orderer smart bft cluster.
• Do 5 TXs.
• Shut down o4.
• Do 5 more TXs.
• Shutdown o1,o2,o3
• Prepare 3 orderer mocks with 10 TXs, with the addresses of o1,o2,o3
  • same mocks as used in the peer test
  • emulate block censorship
• Start o4
• O4 should detect the block censorship attempt and get all 10 blocks to its ledger