feat: signer: support encoding fixed and dynamic arrays to fully comply with EIP 712 spec

[naveen-imtb]

This PR patches the current implementation to resolve this issue.

The test cases in testdata/typed-data.json have been repurposed from the ethers.js repository.

The test cases have been updated to remove the ones that don't have a valid domain separator as EIP-712 messages without a domain separator are not supported by geth.

As an example, the below test case from ethersjs repository has been removed as it is considered invalid.

  {
    "name": "random-33",
    "domain": {},
    "primaryType": "Struct3",
    "types": {
      "EIP712Domain": [],
      "Struct3": [
        {
          "name": "param2",
          "type": "bool"
        }
      ]
    },
    "data": {
      "param2": false
    },
    "digest": "0x1d066e0e8e8e4eaedde581dc40a550c2d6774f57126a6eb0dee143bfb6b3f949"
  },

[holiman]

Nice, I like it that you reused testcases from ethers. I will try to get this reviewed and merged, but it might take a while.

[holiman]

LGTM