Reorganize the stop sequence of modules

[aidan-kwon]

Proposed changes

When (*cn) Stop() is called, it stops blockchain and then stops chainDB.

s.blockchain.Stop()
// stop others
s.chainDB.Close()

However, blockchain still processes inserted block and tries to write data to chainDB.
Because of this, chainDB may closes databases during the data insertion and remains incomplete data in databases.

With this PR, protocolManger, which fetch blocks from other nodes, will be closed earlier than others.

Related PR: ethereum/go-ethereum#20695

Types of changes

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• Bugfix
• New feature or enhancement
• Others

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[KimKyungup]

Permanent lock is general way to for this case?
It means there is a goroutine never return even if process gets kill signal.
Is it ok?

[aidan-kwon]

Permanent lock is general way to for this case?
It means there is a goroutine never return even if process gets kill signal.
Is it ok?

I revised this PR. PTAL

[KimKyungup]

LGTM.