[addrman] Remove AddrMan friends
AddrMan's friends both inherit from AddrMan, so just make the private
member protected and remove the friends.
[addrman] [tests] Tidy up unused arguments in addrman test functions
[addrman] [tests] Remove AddrManCorrupted subclass
It's only used to create a corrupted peers.dat file. We can do that directly
in a pure function.
[addrman] [tests] Remove AddrManUncorrupted subclass
It doesn't do anything different from the base AddrMan class.
This is a backport of core#23477
Commit 7784a9a (*Remove deterministic argument and member from AddrManTest*) is not applicable as it was done in D11827