Invalid characters for a wallet name, e.g. `bitcoin-qt -wallet=你好` used to result in an error like this

<img width="494" alt="schermafbeelding 2018-07-24 om 17 46 37" src="https://user-images.githubusercontent.com/10217/43150553-7bdf598a-8f6a-11e8-8972-44c311a57e56.png">

But now it just crashes:

<img width="509" alt="schermafbeelding 2018-07-24 om 17 43 26" src="https://user-images.githubusercontent.com/10217/43150605-9cf32192-8f6a-11e8-9333-87d074c8dd35.png">

I didn't do a `git bisect`, but it broke somewhere this year :-)
{
    
    
    
    
    
    bool ret = ::AcceptToMemoryPool(mempool, state, tx, nullptr ,
                                nullptr , false , nAbsurdFee);
    fInMempool |= ret;
    return ret;
}
void CWallet::LearnRelatedScripts(const CPubKey& key, OutputType type)
{
    if (key.IsCompressed() && (type == OutputType::P2SH_SEGWIT || type == OutputType::BECH32)) {
        CTxDestination witdest = WitnessV0KeyHash(key.GetID());
        CScript witprog = GetScriptForDestination(witdest);
        
        assert(IsSolvable(*this, witprog));
        AddCScript(witprog);
    }
}
void CWallet::LearnAllRelatedScripts(const CPubKey& key)
{
    
    LearnRelatedScripts(key, OutputType::P2SH_SEGWIT);
}
std::vector<OutputGroup> CWallet::GroupOutputs(const std::vector<COutput>& outputs, bool single_coin) const {