Cardano Updates

Changelog for `cardano-node-10.7`

Added the following tests:

* JSON roundtrip property test
* Unit test for trying to decode an empty object `{}` for the
  `NonEmptyMap`, and an empty list `[]` for the `NonEmptySet`. These
  scenarios are expected to fail with a specific error message.

OutboundSourcePort causes replacement connections to the same peer to
get the same connection ID. The old connection's cleanup goroutine
would unconditionally delete the map entry, destroying the new
connection's registration. Guard the delete with a pointer comparison
so stale cleanups are no-ops.

Signed-off-by: wcatz <[email protected]>

# Conflicts:
#	ouroboros/chainsync.go
#	ouroboros/chainsync_test.go

Include the epoch nonce in the leader schedule log line so nonce
correctness can be verified without querying the database directly.

Signed-off-by: wcatz <[email protected]>

Transactions with isValid=false are consensus-valid on Cardano: the
block producer determined the Plutus script failure, and collateral
is consumed instead of regular inputs. The gouroboros Transaction
interface already handles this via Consumed()/Produced() which return
the correct collateral-based UTxO sets.

Previously dingo ran ValidateTxFunc on all transactions regardless of
the isValid flag, causing phase-1 UTxO validation rules to reject the
block (e.g. bad inputs, value not conserved) because they checked the
regular inputs which were never consumed on-chain.

Gate the ValidateTxFunc call on tx.IsValid() so phase-2 failed TXs
are recorded with their collateral effects without triggering spurious
block validation failures.

Signed-off-by: wcatz <[email protected]>