imp(evm): stateless custom precompiles

[fedekunze]

Description

This PR refactors the EVM module to support custom stateless precompiled contracts by wrapping the go-ethereum EVM into an interface.

This is the first step toward supporting modular EVM implementations with stateful precompiles.

Note: the concrete implementation and tests will be added in a follow-up PR, since the EVM wrapper is not hooked into the state transition at the moment.

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• Wrote unit and integration tests
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• Added relevant godoc comments.
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[codecov]

Codecov Report

Merging #1272 (be3e9d9) into main (723443a) will increase coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1272      +/-   ##
==========================================
+ Coverage   54.78%   54.80%   +0.01%     
==========================================
  Files         107      107              
  Lines        9984     9988       +4     
==========================================
+ Hits         5470     5474       +4     
  Misses       4243     4243              
  Partials      271      271              

Impacted Files	Coverage Δ
app/ante/eth.go	80.05% <100.00%> (ø)
app/app.go	86.07% <100.00%> (ø)
x/evm/keeper/keeper.go	80.23% <100.00%> (+0.23%)	⬆️
x/evm/keeper/state_transition.go	77.03% <100.00%> (+0.13%)	⬆️
x/evm/statedb/journal.go	100.00% <100.00%> (ø)
x/evm/statedb/statedb.go	99.20% <100.00%> (ø)

[Vvaradinov]

Overall good usage of the geth library for the purpose of precompiled contracts. Fixed a couple of typos in the comments above functions. The only other suggestion I see appropriate is the creation of an additional function that will handle RunStatefulPrecompiledContract.

[CoderShiun]

LGTM.

[danburck]

@fedekunze LGTM

It would be helpful to add more context to this PR placing it into the grand scheme of the overall spec.

[loredanacirstea]

I based my stateful and state-using precompiles work on modifying geth to receive a custom precompile list.
But I like @fedekunze 's approach better. Wrapping the go-ethereum/core/vm constructor into an interface that remains compatible with itself is better and does not require changes from the go-ethereum team.
I wish I knew more about Go interfaces and this trick back in February:

type EVM struct {
	*vm.EVM
}

I have not tested this PR yet, but I will use this as a base (instead of #1131 (comment)), for my precompiles work and see how it works.

[loredanacirstea]

utACK
Wrapping the go-ethereum/core/vm constructor into an interface that remains compatible with itself is better and does not require changes from the go-ethereum team.