[tests] Make deterministic addrman use nKey = 1
Summary:
addrman_tests fail when consistency checks are enabled, since the tests set the deterministic test addrman's nKey value to zero, which is an invalid value. Change this so that deterministic addrman's nKey value is set to 1. This requires updating a few tests that are using magic values derived from nKey being set to 0.
Partial backport of core#20233:
https://github.com/bitcoin/bitcoin/pull/20233/commits/10aac241455a3270462d49b53732477ed97623e7
Depends on D12270.
Test Plan:
With DEBUG_ADDRMAN:
ninja all check
Reviewers: #bitcoin_abc, PiRK
Reviewed By: #bitcoin_abc, PiRK
Differential Revision: https://reviews.bitcoinabc.org/D12271