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.
bool fRevertToInv = ((!state.fPreferHeaders &&
                                 (!state.fPreferHeaderAndIDs || pto->vBlockHashesToAnnounce.size() > 1)) ||
                                pto->vBlockHashesToAnnounce.size() > MAX_BLOCKS_TO_ANNOUNCE);
            const CBlockIndex *pBestIndex = nullptr; 
            ProcessBlockAvailability(pto->GetId()); 
            if (!fRevertToInv) {
                bool fFoundStartingHeader = false;
                
                
                
                for (const uint256 &hash : pto->vBlockHashesToAnnounce) {
                    const CBlockIndex* pindex = LookupBlockIndex(hash);
                    assert(pindex);
                    if (::ChainActive()[pindex->nHeight] != pindex) {
                        
                        fRevertToInv = true;
                        break;
                    }
                    if (pBestIndex != nullptr && pindex->pprev != pBestIndex) {