Handle computation of stakes in parallel

[danil-lashin]

Currently stake values re-computed each 12 blocks. In worst case node should calculate 256x3x1 000=768 000 values. This can and should be done in parallel.

minter-go-node/core/state/statedb.go

Lines 926 to 956 in dd284db

	func (s *StateDB) RecalculateTotalStakeValues() {
	stateCandidates := s.getStateCandidates()
	validators := s.getStateValidators()
	for i := range stateCandidates.data {
	candidate := &stateCandidates.data[i]
	totalBipStake := big.NewInt(0)
	for j := range candidate.Stakes {
	stake := &candidate.Stakes[j]
	stake.BipValue = stake.CalcBipValue(s)
	totalBipStake.Add(totalBipStake, stake.BipValue)
	}
	candidate.TotalBipStake = totalBipStake
	for j := range validators.data {
	if bytes.Equal(validators.data[j].PubKey, candidate.PubKey) {
	validators.data[j].TotalBipStake = totalBipStake
	break
	}
	}
	}
	s.setStateValidators(validators)
	s.MarkStateValidatorsDirty()
	s.setStateCandidates(stateCandidates)
	s.MarkStateCandidateDirty()
	}