bench: remove unnecessary CMTxn constructors

Author: instagibbs

src/bench/mempool_ephemeral_spends.cpp

@@ -43,7 +43,7 @@ static void MempoolCheckEphemeralSpends(benchmark::Bench& bench)
     }
 
     // Tx with many outputs
-    CMutableTransaction tx1 = CMutableTransaction();
+    CMutableTransaction tx1;
     tx1.vin.resize(1);
     tx1.vout.resize(number_outputs);
     for (size_t i = 0; i < tx1.vout.size(); i++) {
@@ -55,7 +55,7 @@ static void MempoolCheckEphemeralSpends(benchmark::Bench& bench)
     const auto& parent_txid = tx1.GetHash();
 
     // Spends all outputs of tx1, other details don't matter
-    CMutableTransaction tx2 = CMutableTransaction();
+    CMutableTransaction tx2;
     tx2.vin.resize(tx1.vout.size());
     for (size_t i = 0; i < tx2.vin.size(); i++) {
         tx2.vin[0].prevout.hash = parent_txid;