Function fake_v6_transaction 

pub fn fake_v6_transaction(
    network_upgrade: NetworkUpgrade,
    orchard_shielded_data: Option<ShieldedDataV6>,
    ironwood_shielded_data: Option<ShieldedData>,
) -> Transaction

Builds a minimal NU6.3 v6 Transaction carrying the given optional Orchard-v6 and Ironwood bundles, for structural consensus-rule tests.

The transaction is non-coinbase (no inputs) and otherwise empty. The bundles are not cryptographically valid (see fake_v6_orchard_shielded_data).