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.
Strictly speaking this is not a true deduplication; the test output will be
slightly different (due to inconsistent print statements) but I think this is
close enough.
The mempool was not synced so a block could be generated and not
clear out the mempool. This would then cause subsequent code
which expected the mempool of all nodes to be empty to hang.
The new parameter is to satisfy the principle of least astonishment
by providing a sensible default for the maximum number of transparent
inputs to shield. If users do not configure -mempooltxinputlimit
it is possible for them to create transactions with hundreds of
inputs which suffer from mining delay, due to the current state of
the network where some miners have configured -mempooltxinputlimit
as a way to deal with the problem of quadratic hashing.