feat: allow balance, code, nonce, and state overrides in eth_call

[domob1812]

This PR adds support for overriding the contract code and storage and the account balance and nonce for simulations with eth_call. This feature is similarly supported by geth.

The eth_call RPC method now accepts a third override parameter which is a map from an address to the desired state of that address. The state object has the following keys, all of which are optional:

balance: QUANTITY - The balance to set for the account before executing the call.
nonce: QUANTITY - The nonce to set for the account before executing the call.
code: DATA - The EVM bytecode to set for the account before executing the call.
state*: OBJECT - Key-value mapping of storage slot to value that will clear all slots and then override individual slots in the account storage before executing the call.
stateDiff*: OBJECT - Key-value mapping of storage slot to value that will override individual slots in the account storage before executing the call.
*Note - state and stateDiff fields are mutually exclusive.

So, an example override object using all fields overriding multiple addresses could look like the following:

{
  "0xd9c9cd5f6779558b6e0ed4e6acf6b1947e7fa1f3": { 
    "nonce": "0xa", 
    "balance": "0xffff", 
    "state": { 
      "0000000000000000000000000000000000000000000000000000000000000001": "0xbaddad42baddad42baddad42baddad42baddad42baddad42baddad42baddad42"
    } 
  },
  "0xebe8efa441b9302a0d7eaecc277c09d20d684540": { 
    "code": "0x123456", 
    "stateDiff": {
      "0000000000000000000000000000000000000000000000000000000000000002": "0xbaddad42baddad42baddad42baddad42baddad42baddad42baddad42baddad42"
    } 
  }
}

Like all state changes made with eth_call, the changes are ephemeral and only last for that specific run of eth_call. We'd like to give a huge thank you to @domob1812 and @dekz for their initial contributions to this one, you both were a huge help.

The PR introducing this feature uses @dekz's #905 as a starting point, and fixes #554 and #2934.

[domob1812]

Note that geth also supports overriding storage slots, which this PR does not yet implement (because I personally don't need it and also #905 did not implement it).

I think this can be added as a follow-up when needed. But if you prefer to include support with this PR, let me know and I can try to add it.

[MicaiahReid]

@domob1812 Thank you for the PR! We are reviewing and adding support for overriding storage slots while we're at it. This should hopefully be available in the next release!

[domob1812]

Ok cool, thanks a lot! If you need any help from my side, let me know. I can also work on the storage slots, although I guess you know the involved code much better than me (of course).

[davidmurdoch]

Looking really great! Exciting to finally see this feature land!

I've requested some changes. Let me know if either of you (@domob1812 @MicaiahReid ) have questions or disagree with any of my comments!

[MicaiahReid]

I've done a lot of testing in Geth to see how their eth_call overrides work. Here are the results:

Override Type	Tested Value	Geth Response
Balance	null	Balance remains
Balance	""	Balance 0
Balance	"0x", undefined, "123", {}, 123, -9	Rejected
Code	null	Code remains
Code	""	Clears code
Code	"0x"	Clears code
Code	undefined, "123", {}, 123, -9	Rejected
StateDiff	setting value to:null, "0xbaddad42", "", "0x", undefined, "123", {}, 123, -9	Rejected
StateDiff	setting slot to:null, "0xbaddad42", "", "0x", undefined, "123", {}, 123, -9	Rejected
State	setting value to:null, "0xbaddad42", "", "0x", undefined, "123", {}, 123, -9	Rejected
State	setting slot to:null, "0xbaddad42", "", "0x", undefined, "123", {}, 123, -9	Rejected
Nonce	null	Accepted - makes same contract hash as not overriding nonce
Nonce	""	Accepted - sets nonce to "0x0"
Nonce	"0x", undefined, "123", {}, 123, -9	Rejected

I've made updates so that Ganache behaves the same way, but there's some very specific data validation that we're now doing in the applySimulationOverrides that makes me wonder if we should have some more general rpc data types that align with Geth's.

Also, we should probably consider matching our evm_setAccountNonce, evm_setAccountBalance, evm_setAccountCode, and evm_setAccountStorageAt implementations to have the same data validation as this.

[davidmurdoch]

meant to request changes on the last review. so i'm reeviewing again.

[davidmurdoch]

<3