blockchain/vm: sstore gas cost change (eip2200)

[yoomee1313]

Proposed changes

• This PR implements eip2200 istanbul hardfork item. It is a part of istanbul compatible change. The hardfork number is nil, so it is not activated yet.
• I referenced eip2200 implementation and ethereum/go-ethereum@dcc7fc6. Only SubRefund function is from eip1283 implementation.
• This PR is written above blockchain/state: utilize dirtyStorage more accurately #993. (for now, the PR is not merged, so it contains whole code including PR 993 part)
• Main idea: sstore gas cost change
  • sstore has dynamic gas cost function (sometimes it is called gas metering function. Ethereum tried to upgrade sstore gas cost function at constantinople, but it was not successful. However, eip2200 did it successfully, and it is included in istanbul.
  • before this PR, sstore gas cost function works simple, and it wasn't accurate. By this PR, original value(the value of the state at beginning of the transaction execution) is utilized for accurate gas metering.

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Further comments

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[jeongkyun-oh]

@yoomee1313 If you reference the associated Ethereum PR, it would be nicer.

[aidan-kwon]

@yoomee1313 Geth added one more PR on this change ethereum/go-ethereum#21605 .
Will you apply it later or it is not needed for the next version?

[yoomee1313]

@aidan-kwon oh.. thanks for letting me know about 21605 PR. It is not needed for the next version.. However, in case of bringing berlin hardfork in future, i'll apply it.