eth/tracers: add txHash to pre-bedrock historical trace results

[bbaktaeho]

Description

When querying debug_traceBlockXXX RPC methods on pre-Bedrock blocks, the txHash field is missing in the results.
Below is an example from block number 4, using debug_traceBlockByNumber with the callTracer:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": [
    {
      "txHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
      "result": {
        "from": "0x7107142636c85c549690b1aca12bdb8052d26ae6",
        "gas": "0x2130",
        "gasUsed": "0x2130",
        "input": "0xbede39b500000000000000000000000000000000000000000000000000000029a05f69e1",
        "output": "0x",
        "time": "1.804646ms",
        "to": "0x420000000000000000000000000000000000000f",
        "type": "CALL",
        "value": "0x0"
      }
    }
  ]
}

As you can see, txHash is set to a zero hash.
This PR initializes the txHash field using the corresponding transaction from the block that was traced.

real result:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": [
    {
      "txHash": "0xc1d20abbdd2a63df8dcd8eba2bdcf850d067109dd626964a9987747a154b8fdb",
      "result": {
        "from": "0x7107142636c85c549690b1aca12bdb8052d26ae6",
        "gas": "0x2130",
        "gasUsed": "0x2130",
        "input": "0xbede39b500000000000000000000000000000000000000000000000000000029a05f69e1",
        "output": "0x",
        "time": "34.258333ms",
        "to": "0x420000000000000000000000000000000000000f",
        "type": "CALL",
        "value": "0x0"
      }
    }
  ]
}

Tests

Additional context

Metadata

[teddyknox]

/ci authorize 0d73c8f