Let WaitIfUpstreamIdle spin long enough to stay saturated by load_tester

benchmarks/bench_volatile_loop.cpp

@@ -1,12 +1,14 @@
 #include <nanobench.h>
 
+#include "../src/loop_iterations.h"
+
 int main() {
-  constexpr int loopIterations = 800;
-  ankerl::nanobench::Bench().run(
-      "volatile loop to " + std::to_string(loopIterations), [&] {
-        for (volatile int i = 0; i < loopIterations; i = i + 1)
-          ;
-      });
+  ankerl::nanobench::Bench bench;
+  bench.minEpochIterations(100000);
+  bench.run("volatile loop to " + std::to_string(loopIterations), [&] {
+    for (volatile int i = 0; i < loopIterations; i = i + 1)
+      ;
+  });
 
   return 0;
 }