Refactor microbenchmarks

- Report CPU frequency only if it is successfully queried

PiperOrigin-RevId: 345756568
diff --git a/bench/f32-igemm.cc b/bench/f32-igemm.cc
index 2a961fa..a14cb43 100644
--- a/bench/f32-igemm.cc
+++ b/bench/f32-igemm.cc
@@ -145,7 +145,11 @@
     }
   }
 
-  state.counters["Freq"] = benchmark::utils::GetCurrentCpuFrequency();
+  const uint64_t cpu_frequency = benchmark::utils::GetCurrentCpuFrequency();
+  if (cpu_frequency != 0) {
+    state.counters["cpufreq"] = cpu_frequency;
+  }
+
   state.counters["FLOPS"] = benchmark::Counter(
     uint64_t(state.iterations()) * 2 *
       output_height * output_width *