AccountAccessParser Improvement

[ElliotFriedman]

The AccountAccessParser library has lots of duplicate code looping over an array of VmSafe.AccountAccess and then subsequently looping over the array of storageAccesses contained inside each AccountAccess entry.

It would be nice to have a function that returns an array of all storage writes for a given AccountAccess array.

This function would allow us to remove duplicate code in functions getUniqueWrites and getStateDiffFor.

[ElliotFriedman]

This issue should not block mainnet as this is a small refactor/cleanup.

[blmalone]

Closing as AccountAccessParser has been refactored since this.