bench: clean up includes

Drops unneeded and adds missing includes

src/bench/bench_bitcoin.cpp

@@ -9,7 +9,11 @@
 #include <util/strencodings.h>
 #include <util/system.h>
 
-#include <memory>
+#include <chrono>
+#include <cstdint>
+#include <iostream>
+#include <sstream>
+#include <vector>
 
 static const char* DEFAULT_BENCH_FILTER = ".*";
 static constexpr int64_t DEFAULT_MIN_TIME_MS{10};