[move-only] Move CAddrInfo to test-only header file

Summary:

Now that no bitcoind callers require knowledge of the CAddrInfo object, it can be moved into the test-only header file.

Partial backport of core#22950:
https://github.com/bitcoin/bitcoin/pull/22950/commits/e3f1ea659c9eb1e8be4579923d6acaaab148c2ef#diff-164bd9e2e30f54d0a79eb7cc372309e2f2155edc6c3f051290ab078f03f6a771

Depends on D12330.

Test Plan:

ninja all check
ninja bitcoin-fuzzers

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D12331