VMOpts and VM should use BlockchainInterface and not Blockchain

[alcuadrado]

From @holgerd77: depends on #1181

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Another problem I found when upgrading to v5 is that the VM and its options object use Blockchain and not BlockchainInterface.

The reason I originally proposed to have an interface for blockchain was that @ethereumjs/blockchain is a particular implementation of a blockchain, which doesn't match our usecase. Using the interface in the VM would let us use our own implementation without requiring any hack like casting to any.

I tried replacing it, but unfortunately the vm depends on Blockchain#initPromise, which I think should be removed, as explained in #1181. Once that's resolved, this issue can be fixed by just changing 3 lines of code.

[holgerd77]

Ok, thanks for reporting. From what I read I guess we can put this to mid-urgent? Guess it would be hard to tackle this for this imminent release round (or let me know if I misread and this is a blocker for you).

[alcuadrado]

This is not a blocker right now. We implemented BlockchainInterface in our blockchain, and just sparkled a few as any to make it work. It's fragile, but works for now.

[holgerd77]

Blockchain dependency has been removed from the VM along v6 work, will close here.