`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++`
CScriptCheck check(coins[tx.vin[i].prevout.n].out, tx, i, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS, false, &txdata);
        vChecks.push_back(CScriptCheck());
        check.swap(vChecks.back());
        control.Add(vChecks);
    }
    bool controlCheck = control.Wait();
    assert(controlCheck);
    threadGroup.interrupt_all();
    threadGroup.join_all();
}
SignatureData CombineSignatures(const CMutableTransaction& input1, const CMutableTransaction& input2, const CTransactionRef tx)
{
    SignatureData sigdata;
    sigdata = DataFromTransaction(input1, 0, tx->vout[0]);
    sigdata.MergeSignatureData(DataFromTransaction(input2, 0, tx->vout[0]));
    ProduceSignature(DUMMY_SIGNING_PROVIDER, MutableTransactionSignatureCreator(&input1, 0, tx->vout[0].nValue), tx->vout[0].scriptPubKey, sigdata);
    return sigdata;
}
BOOST_AUTO_TEST_CASE(test_witness)
{
    FillableSigningProvider keystore, keystore2;
    CKey key1, key2, key3, key1L, key2L;
    CPubKey pubkey1, pubkey2, pubkey3, pubkey1L, pubkey2L;
    key1.MakeNewKey(true);
    key2.MakeNewKey(true);
    key3.MakeNewKey(true);
    key1L.MakeNewKey(false);
    key2L.MakeNewKey(false);
    pubkey1 = key1.GetPubKey();
    pubkey2 = key2.GetPubKey();