Steps to reproduce:

* Build with `integer` sanitizer
* `UBSAN_OPTIONS="suppressions=$(pwd)/test/sanitizer_suppressions/ubsan:print_stacktrace=1:halt_on_error=1:report_error_type=1" ./src/qt/bitcoin-qt`
* Enter into the RPC debug console: `decodepsbt "cHNidP8BAKOro2MDAwMDA5ggCAAA////CQAtAAD+///1AAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAJAAAAAAAAAAAAAAAAAAAAAAAAAD+///1Zm9ybmV3nWx1Y2vmelLmegAAAAAAAAAAAAAAAAAAAAMKAwMDAwMDAwMDAwMACvMBA3FkAAAAAAAAAAAABAAlAAAAAAAAACEWDQ0zDQ0NDQ0NDQ0NCwEAAH9/f39/fwMAAABNo6P///kAAA=="`
}
                    if (partial_sigs.count(pubkey.GetID()) > 0) {
                        throw std::ios_base::failure("Duplicate Key, input partial signature for pubkey already provided");
                    }
                    
                    std::vector<unsigned char> sig;
                    s >> sig;
                    
                    partial_sigs.emplace(pubkey.GetID(), SigPair(pubkey, std::move(sig)));
                    break;
                }
                case PSBT_IN_SIGHASH:
                    if (!key_lookup.emplace(key).second) {
                        throw std::ios_base::failure("Duplicate Key, input sighash type already provided");
                    } else if (key.size() != 1) {
                        throw std::ios_base::failure("Sighash type key is more than one byte type");
                    }
                    int sighash;
                    UnserializeFromVector(s, sighash);
                    sighash_type = sighash;
                    break;
                case PSBT_IN_REDEEMSCRIPT:
                {
                    if (!key_lookup.emplace(key).second) {
                        throw std::ios_base::failure("Duplicate Key, input redeemScript already provided");
                    } else if (key.size() != 1) {
                        throw std::ios_base::failure("Input redeemScript key is more than one byte type");
                    }
                    s >> redeem_script;
                    break;