src: add fast loop idle time variation

```
perf_hooks/bench-eventlooputil.js method='ELU_passed' n=1000000                 1.18 %       ±2.02% ±2.69% ±3.50%
perf_hooks/bench-eventlooputil.js method='ELU_simple' n=1000000        ***      7.29 %       ±1.84% ±2.45% ±3.19%
perf_hooks/bench-eventlooputil.js method='idleTime' n=1000000           **      4.20 %       ±2.97% ±3.96% ±5.15%
```

Author: jasnell

benchmark/worker/bench-eventlooputil.js

@@ -8,7 +8,7 @@ if (process.argv[2] === 'idle cats') {
 }
 
 const bench = common.createBenchmark(main, {
-  n: [1e6],
+  n: [1e7],
   method: [
     'ELU_simple',
     'ELU_passed',

src/node_external_reference.h

@@ -38,6 +38,10 @@ using CFunctionCallbackReturnInt32 =
                 v8::FastApiCallbackOptions& options);
 using CFunctionCallbackValueReturnDouble =
     double (*)(v8::Local<v8::Value> receiver);
+using CFunctionCallbackValueReturnDoubleOptions =
+    double (*)(v8::Local<v8::Value>,
+               // NOLINTNEXTLINE(runtime/references) This is V8 api.
+               v8::FastApiCallbackOptions&);
 using CFunctionCallbackValueReturnDoubleUnusedReceiver =
     double (*)(v8::Local<v8::Value> unused, v8::Local<v8::Value> receiver);
 using CFunctionCallbackWithInt64 = void (*)(v8::Local<v8::Object> unused,
@@ -108,6 +112,7 @@ class ExternalReferenceRegistry {
   V(CFunctionCallbackReturnDouble)                                             \
   V(CFunctionCallbackReturnInt32)                                              \
   V(CFunctionCallbackValueReturnDouble)                                        \
+  V(CFunctionCallbackValueReturnDoubleOptions)                                 \
   V(CFunctionCallbackValueReturnDoubleUnusedReceiver)                          \
   V(CFunctionCallbackWithInt64)                                                \
   V(CFunctionCallbackWithBool)                                                 \

src/node_perf.cc

@@ -17,6 +17,7 @@ namespace performance {
 using v8::Array;
 using v8::Context;
 using v8::DontDelete;
+using v8::FastApiCallbackOptions;
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::GCCallbackFlags;
@@ -263,6 +264,15 @@ void LoopIdleTime(const FunctionCallbackInfo<Value>& args) {
   args.GetReturnValue().Set(1.0 * idle_time / NANOS_PER_MILLIS);
 }
 
+static double FastLoopIdleTime(v8::Local<v8::Value> receiver,
+    FastApiCallbackOptions& options) {  // NOLINT(runtime/references)
+  Environment* env = Environment::GetCurrent(options.isolate);
+  uint64_t idle_time = uv_metrics_idle_time(env->event_loop());
+  return 1.0 * idle_time / NANOS_PER_MILLIS;
+}
+
+static v8::CFunction fast_loop_idle_time(v8::CFunction::Make(FastLoopIdleTime));
+
 void UvMetricsInfo(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   Isolate* isolate = env->isolate();
@@ -338,7 +348,8 @@ static void CreatePerIsolateProperties(IsolateData* isolate_data,
             "removeGarbageCollectionTracking",
             RemoveGarbageCollectionTracking);
   SetMethod(isolate, target, "notify", Notify);
-  SetMethod(isolate, target, "loopIdleTime", LoopIdleTime);
+  SetFastMethodNoSideEffect(
+      isolate, target, "loopIdleTime", LoopIdleTime, &fast_loop_idle_time);
   SetMethod(isolate, target, "createELDHistogram", CreateELDHistogram);
   SetMethod(isolate, target, "markBootstrapComplete", MarkBootstrapComplete);
   SetMethod(isolate, target, "uvMetricsInfo", UvMetricsInfo);
@@ -406,6 +417,8 @@ void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
   registry->Register(RemoveGarbageCollectionTracking);
   registry->Register(Notify);
   registry->Register(LoopIdleTime);
+  registry->Register(FastLoopIdleTime);
+  registry->Register(fast_loop_idle_time.GetTypeInfo());
   registry->Register(CreateELDHistogram);
   registry->Register(MarkBootstrapComplete);
   registry->Register(UvMetricsInfo);