bench: Remove requirement that all benches use RegTestingSetup

src/bench/mempool_stress.cpp

@@ -4,6 +4,7 @@
 
 #include <bench/bench.h>
 #include <policy/policy.h>
+#include <test/util/setup_common.h>
 #include <txmempool.h>
 
 #include <vector>
@@ -73,6 +74,7 @@ static void ComplexMemPool(benchmark::State& state)
         ordered_coins.emplace_back(MakeTransactionRef(tx));
         available_coins.emplace_back(ordered_coins.back(), tx_counter++);
     }
+    TestingSetup test_setup;
     CTxMemPool pool;
     LOCK2(cs_main, pool.cs);
     while (state.KeepRunning()) {