insert_relevant_txs
The `insert_relevant_txs` test has also been changed to used `KeychainTxOutIndex` so that index additions can be checked (`SpkTxOutIndex` has no additions). Additionally, generic bounds of some `IndexedTxGraph` list methods have been fixed.
Ensure `insert_relevant_txs` does not require transactions to be in topological order. Other changes: Rm `try_list_owned_txs` as it is useless