For every peer expose through `getpeerinfo` RPC whether or not we selected them as HB peers, and whether or not they selected us as HB peers.

Suggestion by @gmaxwell.
{
    
    int extra_peers = m_connman.GetExtraOutboundCount();
    if (extra_peers > 0) {
        
        
        
        
        NodeId worst_peer = -1;
        int64_t oldest_block_announcement = std::numeric_limits<int64_t>::max();
        m_connman.ForEachNode([&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
            AssertLockHeld(::cs_main);
            
            if (!pnode->IsOutboundOrBlockRelayConn() || pnode->fDisconnect) return;
            CNodeState *state = State(pnode->GetId());
            if (state == nullptr) return; 
            
            if (state->m_chain_sync.m_protect) return;
            
            if (pnode->m_tx_relay == nullptr) return;
            if (state->m_last_block_announcement < oldest_block_announcement || (state->m_last_block_announcement == oldest_block_announcement && pnode->GetId() > worst_peer)) {
                worst_peer = pnode->GetId();
                oldest_block_announcement = state->m_last_block_announcement;
            }
        });