As segwit is active on testnet, blocks will only be downloaded from NODE_WITNESS peers. Though, exactly those peers are disconnected after `BLOCK_STALLING_TIMEOUT = 2` seconds. I am running master (6e6ab2c)

This behavior is consistent across restarts. Sample [debug.log](http://pastebin.ubuntu.com/23058327/) and [getchaintips](http://pastebin.ubuntu.com/23058325/).

It is possible that I shot my own foot at some point, but it seemed smelly enough to create an issue.

{
    if (!tx.IsCoinBase())
    {
        if (!Consensus::CheckTxInputs(tx, state, inputs, GetSpendHeight(inputs)))
            return false;
        if (pvChecks)
            pvChecks->reserve(tx.vin.size());
        
        
        
        
        
        
        
        
        
        if (fScriptChecks) {
            for (unsigned int i = 0; i < tx.vin.size(); i++) {
                const COutPoint &prevout = tx.vin[i].prevout;
                const CCoins* coins = inputs.AccessCoins(prevout.hash);
                assert(coins);
                
                CScriptCheck check(*coins, tx, i, flags, cacheStore);
                if (pvChecks) {
                    pvChecks->push_back(CScriptCheck());