Support the upcoming plato upgrade on BSC testnet

[setunapo]

Rationale

The next upgrade on BSC testnet will be plato, which coming soon.
You may refer: https://forum.bnbchain.org/t/bnb-chain-upgrades-testnet/934#platoupcoming-3
BSC Erigon need port some hard fork changes to support it.

Implementation

According to the BSC Plato testnet release: bnb-chain/bsc#1596, need to port several PRs to Erigon.
Here is the list:

• upgrade: add PlatoUpgrade system contracts code upgrade bnb-chain/bsc#1574
• upgrade: block height of Plato on testnet bnb-chain/bsc#1594
• fix: recently signed check when slashing unavailable validator bnb-chain/bsc#1547
• feat: remove supports for legacy proof type bnb-chain/bsc#1573

The Broken Sync Issue

v1.0.6 failed to sync the BSC testnet upgrade: Plato, refer: https://github.com/node-real/bsc-erigon/issues
It is caused by a miss handle of the receipt of FastFinality reward distribution.
https://testnet.bscscan.com/txs?block=29861000

// Plato on 29861024
https://testnet.bscscan.com/txs?block=29861200
after Plato, there is a new system transaction: distributeFastFinalityReward, it was not handled correctly.

How To Fix

a.get the latest release: v1.0.7(not yet)
b.reset your node to make sure it clear up the dirty state

//== check you latest stages:
./build/bin/integration print_stages --chain=chapel --datadir=<datadir>

//== reset hash & trie
./build/bin/integration stage_hash_state --datadir=<datadir> --reset --chain=chapel
./build/bin/integration stage_trie --datadir=<datadir> --reset --chain=chapel

//== unwind to the block before Plato(29861024)
./build/bin/integration state_stages --unwind=20 --datadir=<datadir> --chain=chapel 

//== start with the latest release
<just use your original command line>