test: speedup wallet tests by whitelisting peers (immediate tx relay) #25865

In the course of testing #25297 by running all wallet-related functional tests (see #25297 (comment)), I noticed that the run-time of those tests vary a lot between runs, in fact too much for a useful comparison. This PR fixes this by making the tests both more deterministic and also faster, using the good ol' immediate tx relay trick (parameter -whitelist=noban@127.0.0.1).

master branch:

wallet_abandonconflict.py --descriptors   | ✓ Passed  | 7 s
wallet_abandonconflict.py --legacy-wallet | ✓ Passed  | 23 s
wallet_balance.py --descriptors           | ✓ Passed  | 17 s
wallet_balance.py --legacy-wallet         | ✓ Passed  | 21 s
wallet_basic.py --descriptors             | ✓ Passed  | 32 s
wallet_basic.py --legacy-wallet           | ✓ Passed  | 56 s
wallet_bumpfee.py --descriptors           | ✓ Passed  | 44 s
wallet_bumpfee.py --legacy-wallet         | ✓ Passed  | 45 s
wallet_groups.py --descriptors            | ✓ Passed  | 89 s
wallet_groups.py --legacy-wallet          | ✓ Passed  | 94 s
wallet_hd.py --descriptors                | ✓ Passed  | 7 s
wallet_hd.py --legacy-wallet              | ✓ Passed  | 13 s
wallet_importdescriptors.py --descriptors | ✓ Passed  | 26 s
wallet_listreceivedby.py --descriptors    | ✓ Passed  | 28 s
wallet_listreceivedby.py --legacy-wallet  | ✓ Passed  | 18 s

ALL                                       | ✓ Passed  | 520 s (accumulated)
Runtime: 526 s

PR branch:

wallet_abandonconflict.py --descriptors   | ✓ Passed  | 7 s
wallet_abandonconflict.py --legacy-wallet | ✓ Passed  | 11 s
wallet_balance.py --descriptors           | ✓ Passed  | 8 s
wallet_balance.py --legacy-wallet         | ✓ Passed  | 8 s
wallet_basic.py --descriptors             | ✓ Passed  | 29 s
wallet_basic.py --legacy-wallet           | ✓ Passed  | 36 s
wallet_bumpfee.py --descriptors           | ✓ Passed  | 39 s
wallet_bumpfee.py --legacy-wallet         | ✓ Passed  | 32 s
wallet_groups.py --descriptors            | ✓ Passed  | 39 s
wallet_groups.py --legacy-wallet          | ✓ Passed  | 41 s
wallet_hd.py --descriptors                | ✓ Passed  | 8 s
wallet_hd.py --legacy-wallet              | ✓ Passed  | 11 s
wallet_importdescriptors.py --descriptors | ✓ Passed  | 17 s
wallet_listreceivedby.py --descriptors    | ✓ Passed  | 7 s
wallet_listreceivedby.py --legacy-wallet  | ✓ Passed  | 9 s

ALL                                       | ✓ Passed  | 302 s (accumulated)
Runtime: 309 s

Note that an alternative approach could be to whitelist peers by default for nodes in the functional test framework and only enable the trickle relay for the few tests where it's really needed.

Concept ACK on disabling the trickle mechanism on tests that aren't related to network gossip.

The mechanism is specific to the network layer, shouldn't be adding extra noise and indeterminism (time wise) to tests that cover layers that live on top of it.

utACK b21e522ce47a13e024488e43f1cd33a0f1769197