This PR adds a test case for addrman that verifies that addresses announcing themselves (addr == source) are exempt from time penalties, while addresses announced by others receive the expected penalty.
It fixes the following mutant (https://corecheck.dev/mutation/src/addrman.cpp#L561):
0diff --git a/src/addrman.cpp b/src/addrman.cpp
1index 206b54118e..c6a045fd8d 100644
2--- a/src/addrman.cpp
3+++ b/src/addrman.cpp
4@@ -558,7 +558,7 @@ bool AddrManImpl::AddSingle(const CAddress& addr, const CNetAddr& source, std::c
5 AddrInfo* pinfo = Find(addr, &nId);
6
7 // Do not set a penalty for a source's self-announcement
8- if (addr == source) {
9+ if (addr != source) {
10 time_penalty = 0s;
11 }