The p2p_nu_peer_management and rewind_index RPC tests still start from
Sprout, because they are explicitly (and only) testing network behaviour
across network upgrades.
The mempool_tx_input_limit test is removed because the flag has been
ignored since Sapling activation, and will be removed at some point in
the near future.
Don't accept transactions which are about to expire (next 3 blocks).
Don't set a ban score if a peer does propragate these transactions.
See ZEC-013 for more detail.