`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++`
SetupDummyInputs(FillableSigningProvider& keystoreRet, CCoinsViewCache& coinsRet)
{
    std::vector<CMutableTransaction> dummyTransactions;
    dummyTransactions.resize(2);
    
    CKey key[4];
    for (int i = 0; i < 4; i++)
    {
        key[i].MakeNewKey(i % 2);
        keystoreRet.AddKey(key[i]);
    }
    
    dummyTransactions[0].vout.resize(2);
    dummyTransactions[0].vout[0].nValue = 11*CENT;
    dummyTransactions[0].vout[0].scriptPubKey << ToByteVector(key[0].GetPubKey()) << OP_CHECKSIG;
    dummyTransactions[0].vout[1].nValue = 50*CENT;
    dummyTransactions[0].vout[1].scriptPubKey << ToByteVector(key[1].GetPubKey()) << OP_CHECKSIG;
    AddCoins(coinsRet, CTransaction(dummyTransactions[0]), 0);
    dummyTransactions[1].vout.resize(2);
    dummyTransactions[1].vout[0].nValue = 21*CENT;
    dummyTransactions[1].vout[0].scriptPubKey = GetScriptForDestination(PKHash(key[2].GetPubKey()));
    dummyTransactions[1].vout[1].nValue = 22*CENT;
    dummyTransactions[1].vout[1].scriptPubKey = GetScriptForDestination(PKHash(key[3].GetPubKey()));
    AddCoins(coinsRet, CTransaction(dummyTransactions[1]), 0);
    return dummyTransactions;
}
BOOST_AUTO_TEST_CASE(test_Get)