Merge bitcoin/bitcoin#30093: optimization: reserve memory allocation …

…for transaction inputs/outputs

ec585f1 Reserve space for transaction inputs in CreateTransactionInternal (Lőrinc)
c76aaaf Reserve space for transaction outputs in CreateTransactionInternal (Lőrinc)

Pull request description:

  Reserved memory for the transaction inputs and outputs.

  Split out of https://github.com/bitcoin/bitcoin/pull/30050/files#r1597631104

ACKs for top commit:
  achow101:
    ACK ec585f1
  TheCharlatan:
    ACK ec585f1
  stickies-v:
    ACK ec585f1

Tree-SHA512: de399fb19824423467f48af64aa57f41a23cdd00eb17461e0131e4deafdd15e0d2daebf6a0a7ac7728b2fb486b2a54f1a7ef26bbe823c56b2a09f892f6b9a581

src/wallet/spend.cpp

@@ -1167,6 +1167,7 @@ static util::Result<CreatedTransactionResult> CreateTransactionInternal(
            result.GetSelectedValue());
 
     // vouts to the payees
+    txNew.vout.reserve(vecSend.size() + 1); // + 1 because of possible later insert
     for (const auto& recipient : vecSend)
     {
         txNew.vout.emplace_back(recipient.nAmount, GetScriptForDestination(recipient.dest));
@@ -1217,6 +1218,7 @@ static util::Result<CreatedTransactionResult> CreateTransactionInternal(
     // behavior."
     bool use_anti_fee_sniping = true;
     const uint32_t default_sequence{coin_control.m_signal_bip125_rbf.value_or(wallet.m_signal_rbf) ? MAX_BIP125_RBF_SEQUENCE : CTxIn::MAX_SEQUENCE_NONFINAL};
+    txNew.vin.reserve(selected_coins.size());
     for (const auto& coin : selected_coins) {
         std::optional<uint32_t> sequence = coin_control.GetSequence(coin->outpoint);
         if (sequence) {