p2p: Try to connect to anchors once
Summary:
This is a backport of core#17428 [6/7]
https://github.com/bitcoin/bitcoin/pull/17428/commits/0a85e5a7bc8dc6587963e2e37ac1b087a1fc97fe
Depends on D10511
Test Plan: ninja all check-all
Reviewers: #bitcoin_abc, majcosta
Reviewed By: #bitcoin_abc, majcosta
Differential Revision: https://reviews.bitcoinabc.org/D10512