go/oasis-test-runner/byzantine: Add primary+backup liveness test

[kostko]

Non-breaking test part of #4798.

[codecov]

Codecov Report

Merging #4799 (c152b68) into master (aba5861) will decrease coverage by 0.05%.
The diff coverage is 55.55%.

@@            Coverage Diff             @@
##           master    #4799      +/-   ##
==========================================
- Coverage   66.85%   66.80%   -0.06%     
==========================================
  Files         451      451              
  Lines       50300    50278      -22     
==========================================
- Hits        33630    33590      -40     
- Misses      12500    12517      +17     
- Partials     4170     4171       +1     

Impacted Files	Coverage Δ
go/common/sgx/pcs/tcb.go	54.58% <ø> (ø)
go/common/sgx/pcs/quote.go	54.92% <14.28%> (-1.03%)	⬇️
go/oasis-node/cmd/genesis/genesis.go	53.68% <42.85%> (+1.73%)	⬆️
go/common/sgx/pcs/pcs.go	55.55% <53.84%> (-4.45%)	⬇️
...consensus/tendermint/apps/scheduler/debug_force.go	82.55% <100.00%> (ø)
go/consensus/tendermint/apps/scheduler/shuffle.go	69.71% <100.00%> (+0.07%)	⬆️
go/oasis-node/cmd/common/common.go	59.02% <100.00%> (+0.28%)	⬆️
go/scheduler/api/api.go	60.20% <100.00%> (+2.13%)	⬆️
...consensus/tendermint/apps/roothash/transactions.go	66.66% <0.00%> (-6.23%)	⬇️
go/storage/mkvs/lookup.go	75.00% <0.00%> (-4.17%)	⬇️
... and 20 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e2f2cce...c152b68. Read the comment docs.