Not close KVStore iterate after use

[warm3snow]

Summary of Bug

Not closing the KVStore iterate after use, e.g. in x/staking/keeper/validator.go

func (k Keeper) GetAllMatureValidatorQueue(ctx sdk.Context, currTime time.Time) (matureValsAddrs []sdk.ValAddress) {
	// gets an iterator for all timeslices from time 0 until the current Blockheader time
	validatorTimesliceIterator := k.ValidatorQueueIterator(ctx, ctx.BlockHeader().Time) 
	for ; validatorTimesliceIterator.Valid(); validatorTimesliceIterator.Next() {
		timeslice := []sdk.ValAddress{}
		k.cdc.MustUnmarshalBinaryLengthPrefixed(validatorTimesliceIterator.Value(), &timeslice)
		matureValsAddrs = append(matureValsAddrs, timeslice...)
	}
	return matureValsAddrs
}

// Unbonds all the unbonding validators that have finished their unbonding period
func (k Keeper) UnbondAllMatureValidatorQueue(ctx sdk.Context) {
	store := ctx.KVStore(k.storeKey)
	validatorTimesliceIterator := k.ValidatorQueueIterator(ctx, ctx.BlockHeader().Time)
	for ; validatorTimesliceIterator.Valid(); validatorTimesliceIterator.Next() {
		timeslice := []sdk.ValAddress{}
		k.cdc.MustUnmarshalBinaryLengthPrefixed(validatorTimesliceIterator.Value(), &timeslice)
		for _, valAddr := range timeslice {
			val, found := k.GetValidator(ctx, valAddr)
			if !found {
				panic("validator in the unbonding queue was not found")
			}
			if val.GetStatus() != sdk.Unbonding {
				panic("unexpected validator in unbonding queue, status was not unbonding")
			}
			k.unbondingToUnbonded(ctx, val)
			if val.GetDelegatorShares().IsZero() {
				k.RemoveValidator(ctx, val.OperatorAddress)
			}
		}
		store.Delete(validatorTimesliceIterator.Key())
	}
}

validatorTimesliceIterator, validatorTimesliceIterator must be closed before methods return

Version

latest

5f92fef

Steps to Reproduce

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