When use the genesis.json from the ethermintd export operation to restart a new chain, the node will panic

[banishee]

System info: [Include Ethermint commit, operating system name, and other relevant details]
branch: https://github.com/cosmos/ethermint/commits/development

Steps to reproduce:

1. [First Step]

• excute ./init.sh
• make the node commit several blocks, and do some transfering transactions to new accounts
• kill the node
• excute ethermintd export > genesis.json
• use this genesis.json to start a new chain
• then, the node will shows up panic information

I[2021-01-04|15:49:37.671] starting ABCI with Tendermint                module=main 
panic: UnmarshalJSON cannot decode empty bytes

goroutine 1 [running]:
github.com/cosmos/cosmos-sdk/x/params/subspace.Subspace.Get(0xc000184230, 0x54eb7c0, 0xc000023330, 0x54eb800, 0xc0000233c0, 0xc0006b4520, 0x3, 0x12, 0xc0000e2c30, 0x54fe3c0, ...)
        /Users/green/go/pkg/mod/github.com/cosmos/[email protected]/x/params/subspace/subspace.go:106 +0x2b8
github.com/cosmos/cosmos-sdk/x/params/subspace.Subspace.GetParamSet(0xc000184230, 0x54eb7c0, 0xc000023330, 0x54eb800, 0xc0000233c0, 0xc0006b4520, 0x3, 0x12, 0xc0000e2c30, 0x54fe3c0, ...)
        /Users/green/go/pkg/mod/github.com/cosmos/[email protected]/x/params/subspace/subspace.go:217 +0x195
github.com/cosmos/ethermint/x/evm/types.(*CommitStateDB).GetParams(...)
        /Users/green/project/ethermint/x/evm/types/statedb.go:310
github.com/cosmos/ethermint/x/evm/types.(*stateObject).SetBalance(0xc000d859e0, 0xc00024fb80)
        /Users/green/project/ethermint/x/evm/types/state_object.go:201 +0x189
github.com/cosmos/ethermint/x/evm/types.(*CommitStateDB).SetBalance(0xc000501c00, 0x28c5e222c3180c0d, 0xb91a0de2fdafa168, 0xc0a497d964, 0xc00024fb80)
        /Users/green/project/ethermint/x/evm/types/statedb.go:136 +0x6c
github.com/cosmos/ethermint/x/evm/keeper.(*Keeper).SetBalance(...)
        /Users/green/project/ethermint/x/evm/keeper/statedb.go:22
github.com/cosmos/ethermint/x/evm.InitGenesis(0x54fe3c0, 0xc000134008, 0x55145c0, 0xc0000b4680, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
        /Users/green/project/ethermint/x/evm/genesis.go:42 +0x41d
github.com/cosmos/ethermint/x/evm.AppModule.InitGenesis(0xc000184230, 0x54eb7c0, 0xc000023360, 0x5509800, 0xc000184850, 0xc000501c00, 0x0, 0xc00000fec0, 0x5509800, 0xc000184e70, ...)
        /Users/green/project/ethermint/x/evm/module.go:129 +0x192
github.com/cosmos/cosmos-sdk/types/module.(*Manager).InitGenesis(0xc000184fc0, 0x54fe3c0, 0xc000134008, 0x55145c0, 0xc0000b4680, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
        /Users/green/go/pkg/mod/github.com/cosmos/[email protected]/types/module/module.go:265 +0x278
github.com/cosmos/ethermint/app.(*EthermintApp).InitChainer(0xc000151b80, 0x54fe3c0, 0xc000134008, 0x55145c0, 0xc0000b4680, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
        /Users/green/project/ethermint/app/ethermint.go:345 +0x11d
....

Expected behavior: [What you expected to happen]

Actual behavior: [What actually happened]

Additional info: [Include gist of relevant config, logs, etc.]

[fedekunze]

good catch!