Merge bitcoin/bitcoin#26675: wallet: For feebump, ignore abandoned descendant spends

f9ce0eadf4 For feebump, ignore abandoned descendant spends (John Moffett)

Pull request description:

  Closes #26667

  To be eligible for fee-bumping, a transaction must not have any of its outputs (eg - change) spent in other unconfirmed transactions in the wallet. This behavior is currently [enforced](9e229a542f/src/wallet/feebumper.cpp (L25-L28)) and [tested](9e229a542f/test/functional/wallet_bumpfee.py (L270-L286)).

  However, this check shouldn't apply to spends in abandoned descendant transactions, as explained by #26667.

  `CWallet::IsSpent` already carves out an exception for abandoned transactions, so we can just use that.

  I've also added a new test to cover this case.

ACKs for top commit:
  Sjors:
    re-utACK f9ce0eadf4
  achow101:
    ACK f9ce0eadf4
  furszy:
    ACK f9ce0ead

Tree-SHA512: 19d957d1cf6747668bb114e27a305027bfca5a9bed2b1d9cc9e1b0bd4666486c7c4b60b045a7fe677eb9734d746f5de76390781fb1e9e0bceb4a46d20acd1749

src/wallet/wallet.cpp

@@ -647,8 +647,7 @@ bool CWallet::HasWalletSpend(const CTransactionRef& tx) const
     AssertLockHeld(cs_wallet);
     const uint256& txid = tx->GetHash();
     for (unsigned int i = 0; i < tx->vout.size(); ++i) {
-        auto iter = mapTxSpends.find(COutPoint(txid, i));
-        if (iter != mapTxSpends.end()) {
+        if (IsSpent(COutPoint(txid, i))) {
             return true;
         }
     }