Revert reason missing when using geth 1.9.14

[cgewecke]

cf: geth 21082

In geth 1.9.14 no data is returned when replaying failing transactions with eth_call which means Web3 cannot extract the reason.

There's a reproduction case at: https://github.com/cgewecke/geth-revert-reason-repro

[cgewecke]

Related: geth PR 21083, which would format reverting eth_call responses as below:

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32000,
    "message": "some error"
  }
}

[cgewecke]

Note: when this is fixed and geth in CI is restored to stable (instead of 1.9.13), make sure to update the TESTING.md docs to reflect this..