Move bench_volatile_loop to benchmarks/

benchmarks/bench_volatile_loop.cpp

@@ -0,0 +1,12 @@
+#include <nanobench.h>
+
+int main() {
+  constexpr int loopIterations = 1200;
+  ankerl::nanobench::Bench().run(
+      "volatile loop to " + std::to_string(loopIterations), [&] {
+        for (volatile int i = 0; i < 1200; i = i + 1)
+          ;
+      });
+
+  return 0;
+}