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: https://github.com/nodejs/node/pull/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>