`validation_flush_tests/getcoinscachesizestate` fails on RISCV-64 on master:
```
Running 394 test cases...
test/validation_flush_tests.cpp(99): error: in "validation_flush_tests/getcoinscachesizestate": check chainstate.GetCoinsCacheSizeState(tx_pool, MAX_COINS_CACHE_BYTES, 0) == CoinsCacheSizeState::OK has failed [1 != 0]

*** 1 failure is detected in the test module "Bitcoin Core Test Suite"
```
Haven't investigated why, yet. Apart from the architecture it could also be some dependency version causing the problem (this is a fedora rawhide install with very new versions of everything including gcc and boost).

Edit: see below, this is likely due to a newer `libstdc++`
outputm.vout.resize(1);
    outputm.vout[0].nValue = 1;
    outputm.vout[0].scriptPubKey = outscript;
    CDataStream ssout(SER_NETWORK, PROTOCOL_VERSION);
    ssout << outputm;
    ssout >> output;
    assert(output->vin.size() == 1);
    assert(output->vin[0] == outputm.vin[0]);
    assert(output->vout.size() == 1);
    assert(output->vout[0] == outputm.vout[0]);
    CMutableTransaction inputm;
    inputm.nVersion = 1;
    inputm.vin.resize(1);
    inputm.vin[0].prevout.hash = output->GetHash();
    inputm.vin[0].prevout.n = 0;
    inputm.vout.resize(1);
    inputm.vout[0].nValue = 1;
    inputm.vout[0].scriptPubKey = CScript();
    bool ret = SignSignature(keystore, *output, inputm, 0, SIGHASH_ALL);
    assert(ret == success);
    CDataStream ssin(SER_NETWORK, PROTOCOL_VERSION);
    ssin << inputm;
    ssin >> input;
    assert(input.vin.size() == 1);
    assert(input.vin[0] == inputm.vin[0]);
    assert(input.vout.size() == 1);
    assert(input.vout[0] == inputm.vout[0]);
    assert(input.vin[0].scriptWitness.stack == inputm.vin[0].scriptWitness.stack);
}
static void CheckWithFlag(const CTransactionRef& output, const CMutableTransaction& input, int flags, bool success)