src: prefer to get Environment from Context

We explicitly store the context anyway, and can skip the
extra steps introduced in `Environment::GetCurrent()`.

PR-URL: #26376
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/node_perf.cc

@@ -333,10 +333,9 @@ inline Local<Value> GetName(Local<Function> fn) {
 // execution.
 void TimerFunctionCall(const FunctionCallbackInfo<Value>& args) {
   Isolate* isolate = args.GetIsolate();
-  HandleScope scope(isolate);
-  Environment* env = Environment::GetCurrent(isolate);
+  Local<Context> context = isolate->GetCurrentContext();
+  Environment* env = Environment::GetCurrent(context);
   CHECK_NOT_NULL(env);
-  Local<Context> context = env->context();
   Local<Function> fn = args.Data().As<Function>();
   size_t count = args.Length();
   size_t idx;