Merge #20575: Do not run functions with necessary side-effects in assert()

5021810650 Make CanFlushToDisk a const member function (practicalswift)
281cf99554 Do not run functions with necessary side-effects in assert() (practicalswift)

Pull request description:

  Do not run functions with necessary side-effects in `assert()`.

ACKs for top commit:
  laanwj:
    Code review ACK 5021810650
  sipa:
    utACK 5021810650
  theStack:
    Code Review ACK 5021810650 🟢

Tree-SHA512: 38b7faccc2f16a499f9b7b1b962b49eb58580b2a2bbf63ea49dcc418a5ecc8f21a0972fa953f66db9509c7239af67cfa2f9266423fd220963d091034d7332b96

src/wallet/test/coinselector_tests.cpp

@@ -64,7 +64,8 @@ static void add_coin(CWallet& wallet, const CAmount& nValue, int nAge = 6*24, bo
     if (spendable) {
         CTxDestination dest;
         std::string error;
-        assert(wallet.GetNewDestination(OutputType::BECH32, "", dest, error));
+        const bool destination_ok = wallet.GetNewDestination(OutputType::BECH32, "", dest, error);
+        assert(destination_ok);
         tx.vout[nInput].scriptPubKey = GetScriptForDestination(dest);
     }
     if (fIsFromMe) {