go/staking: include LastBlockFees in genesis

[ptrus]

Also adds a dump-restore version of the gas-fees test.

[codecov]

Codecov Report

Merging #2777 into master will increase coverage by 0.73%.
The diff coverage is 43.75%.

@@            Coverage Diff             @@
##           master    #2777      +/-   ##
==========================================
+ Coverage   62.44%   63.18%   +0.73%     
==========================================
  Files         389      389              
  Lines       37088    37119      +31     
==========================================
+ Hits        23159    23452     +293     
+ Misses      10969    10667     -302     
- Partials     2960     3000      +40     

Impacted Files	Coverage Δ
...nsus/tendermint/apps/supplementarysanity/checks.go	47.85% <0.00%> (ø)
go/staking/api/api.go	71.42% <ø> (ø)
go/staking/api/sanity_check.go	50.87% <33.33%> (-0.48%)	⬇️
go/consensus/tendermint/apps/staking/genesis.go	43.86% <40.90%> (-0.35%)	⬇️
go/oasis-node/cmd/stake/stake.go	71.54% <66.66%> (-0.26%)	⬇️
...ompute/txnscheduler/algorithm/batching/batching.go	78.66% <0.00%> (-6.67%)	⬇️
go/worker/storage/service_external.go	47.31% <0.00%> (-4.31%)	⬇️
go/worker/common/p2p/p2p.go	64.86% <0.00%> (-2.71%)	⬇️
go/worker/storage/committee/checkpointer.go	66.37% <0.00%> (-1.77%)	⬇️
go/storage/mkvs/urkel/cache.go	81.27% <0.00%> (-1.71%)	⬇️
... and 28 more

---

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[Yawning]

Will this break dump/restore?

[ptrus]

yeah in the first begin block the GetLastCommitInfo will have no votes, so we probably need to also carry over that as well? (or handle differently the initial fee disbursement)

edit: one option moving it into common pool at initialization, this is what is currently implemented in the PR