Fix random trie exception after pruning

[asdacap]

• If full pruning is started after new head event which is triggered by blockchainproccessor where the branch have more than one block, some of the block state will be missed causing trie exception after pruning complete.
• This is because blockchainprocessor will process the branch first before triggered new head event multiple time. Full pruning will start switching duplicating writes after the first event, and assume the writes for the other blocks will start after that, but that does not happen as it was already processed.
• This PR add another event OnUpdateMainChain which would get triggered per processing branch instead of multiple time. Ideally the event should be in BlockchainProcessor, but turns out there is a dependency issue so it can't refer to it without a bigger refactor.

2023-03-21 17:52:14.4630|WARN|46|Process done 8692501 
2023-03-21 17:52:14.4670|WARN|46|Processing 8692502 
2023-03-21 17:52:14.5831|WARN|46|Process done 8692502 
2023-03-21 17:52:14.5879|WARN|46|New head block 8692501 
2023-03-21 17:52:14.5899|WARN|46|Buffer size for State1 20899225 8 3028682281 
2023-03-21 17:52:14.5924|INFO|46|Full Pruning Ready to start: waiting for state 8692501 to be ready. 
2023-03-21 17:52:14.5924|WARN|46|New head block 8692502 
2023-03-21 17:52:14.5924|INFO|46|Full Pruning Waiting for block: 8692511 in order to support reorganizations. 
2023-03-21 17:52:14.5924|INFO|46|Processed    8692502 |      292ms of 802,469ms, mgasps   44.41 total   44.41, tps  396.92 total  396.92, bps    0.00 total    0.00, recv queue 0, proc queue 32 
2023-03-21 17:52:14.5924|WARN|46|Processing 8692503 

Changes

• Use OnUpdateMainChain event instead.
• Updated unit tests to reflect.

Types of changes

What types of changes does your code introduce?

• Bugfix (a non-breaking change that fixes an issue)

Testing

Requires testing

• Yes
• No

If yes, did you write tests?

• Yes: well I updated the old tests.
• No

Notes on testing

• 6 consecutive goerli full pruning so far...

[LukaszRozmej]

What is now the difference between BlockAddedToMain and OnUpdateMainChain? Would be good to document

[asdacap]

Done