Update to consensus-specs v1.1.9 (#3016)

## Issue Addressed

Closes #3014

## Proposed Changes

- Rename `receipt_root` to `receipts_root`
- Rename `execute_payload` to `notify_new_payload`
   - This is slightly weird since we modify everything except the actual HTTP call to the engine API. That change is expected to be implemented in #2985 (cc @ethDreamer)
- Enable "random" tests for Bellatrix.

## Notes

This will break *partially* compatibility with Kintusgi testnets in order to gain compatibility with [Kiln](https://hackmd.io/@n0ble/kiln-spec) testnets. I think it will only break the BN APIs due to the `receipts_root` change, however it might have some other effects too.

Co-authored-by: Michael Sproul <micsproul@gmail.com>

testing/ef_tests/src/handler.rs

@@ -307,11 +307,6 @@ pub struct RandomHandler<E>(PhantomData<E>);
 impl<E: EthSpec + TypeName> Handler for RandomHandler<E> {
     type Case = cases::SanityBlocks<E>;
 
-    // FIXME(merge): enable merge tests once available
-    fn is_enabled_for_fork(&self, fork_name: ForkName) -> bool {
-        fork_name != ForkName::Merge
-    }
-
     fn config_name() -> &'static str {
         E::name()
     }