test: remove unneeded HandleScope usage

These methods are Javascript-accessible so they get an implicit
HandleScope. The extra scope is unneeded and can be dropped.

PR-URL: https://github.com/nodejs/node/pull/13859
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>

test/addons/async-hello-world/binding.cc

@@ -55,7 +55,6 @@ void AfterAsync(uv_work_t* r) {
 
 void Method(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
-  v8::HandleScope scope(isolate);
 
   async_req* req = new async_req;
   req->req.data = req;

test/addons/hello-world-function-export/binding.cc

@@ -3,7 +3,6 @@
 
 void Method(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
-  v8::HandleScope scope(isolate);
   args.GetReturnValue().Set(v8::String::NewFromUtf8(isolate, "world"));
 }
 

test/addons/hello-world/binding.cc

@@ -3,7 +3,6 @@
 
 void Method(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
-  v8::HandleScope scope(isolate);
   args.GetReturnValue().Set(v8::String::NewFromUtf8(isolate, "world"));
 }
 

test/addons/repl-domain-abort/binding.cc

@@ -25,14 +25,12 @@
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::Local;
-using v8::HandleScope;
 using v8::Isolate;
 using v8::Object;
 using v8::Value;
 
 void Method(const FunctionCallbackInfo<Value>& args) {
   Isolate* isolate = args.GetIsolate();
-  HandleScope scope(isolate);
   node::MakeCallback(isolate,
                      isolate->GetCurrentContext()->Global(),
                      args[0].As<Function>(),