[test] remove confusing p2p property
Summary:
This is a backport of core#19804 [4/4]
https://github.com/bitcoin/bitcoin/pull/19804/commits/10d61505fe77880d6989115defa5e08417f3de2d
Depends on D10320, D10321 and D10324
Test Plan: ninja check-functional-extended
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Subscribers: Fabien
Differential Revision: https://reviews.bitcoinabc.org/D10325