net: remove unnecessary check from AlreadyConnectedToAddress()

`CConnman::AlreadyConnectedToAddress()` searches the existent nodes by
address or by address-and-port:

```cpp
FindNode(static_cast<CNetAddr>(addr)) || FindNode(addr.ToStringAddrPort())
```

but:

* if there is a match by just the address, then the address-and-port
  search will not be evaluated and the whole condition will be `true`
* if the there is no node with the same address, then the second search
  by address-and-port will not find a match either.

The search by address-and-port is comparing against `CNode::m_addr_name`
which could be a hostname, e.g. `"node.foobar.com:8333"`, but
`addr.ToStringAddrPort()` is always going to be numeric.

Author: vasild

src/net.cpp

@@ -367,7 +367,7 @@ CNode* CConnman::FindNode(const CService& addr)
 
 bool CConnman::AlreadyConnectedToAddress(const CAddress& addr)
 {
-    return FindNode(static_cast<CNetAddr>(addr)) || FindNode(addr.ToStringAddrPort());
+    return FindNode(static_cast<CNetAddr>(addr));
 }
 
 bool CConnman::CheckIncomingNonce(uint64_t nonce)

src/test/fuzz/netaddress.cpp

@@ -101,10 +101,14 @@ FUZZ_TARGET(netaddress)
     (void)net_addr.GetReachabilityFrom(other_net_addr);
     (void)sub_net.Match(other_net_addr);
 
-    const CService other_service{net_addr, fuzzed_data_provider.ConsumeIntegral<uint16_t>()};
+    const CService other_service{fuzzed_data_provider.ConsumeBool() ? net_addr : other_net_addr, fuzzed_data_provider.ConsumeIntegral<uint16_t>()};
     assert((service == other_service) != (service != other_service));
     (void)(service < other_service);
 
+    if (service.ToStringAddrPort() == other_service.ToStringAddrPort()) {
+        assert(static_cast<CNetAddr>(service) == static_cast<CNetAddr>(other_service));
+    }
+
     const CSubNet sub_net_copy_1{net_addr, other_net_addr};
     const CSubNet sub_net_copy_2{net_addr};