Whenever a transaction is added to the mempool or orphan pool, both
its txid and wtxid are considered AlreadyHave, and thus will eventually
be removed from m_txrequest.

The same is true for hashes added to the reject filter, but note that
sometimes only the wtxid is added (in which case only the wtxid can be
removed from m_txrequest).

ninja all check-all
./test/functional/test_runner.py p2p_tx_download