src: remove unused variables

Currently the following compiler warnings are generated:

../src/node_process.cc:799:16:
warning: unused variable 'ary' [-Wunused-variable]
  Local<Array> ary = Array::New(args.GetIsolate());
               ^
1 warning generated.

../src/node_http2.cc:1294:16:
warning: unused variable 'holder' [-Wunused-variable]
  Local<Array> holder = Array::New(isolate);
               ^
1 warning generated.

This commit removes these unused variables.

PR-URL: #24355
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

src/node_http2.cc

@@ -1291,7 +1291,6 @@ void Http2Session::HandleHeadersFrame(const nghttp2_frame* frame) {
   Local<String> name_str;
   Local<String> value_str;
 
-  Local<Array> holder = Array::New(isolate);
   // The headers are passed in above as a queue of nghttp2_header structs.
   // The following converts that into a JS array with the structure:
   // [name1, value1, name2, value2, name3, value3, name3, value4] and so on.

src/node_process.cc

@@ -796,7 +796,6 @@ void GetParentProcessId(Local<Name> property,
 void GetActiveRequests(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
-  Local<Array> ary = Array::New(args.GetIsolate());
   std::vector<Local<Value>> request_v;
   for (auto w : *env->req_wrap_queue()) {
     if (w->persistent().IsEmpty())