benchmark,lib: change var to const

Refs: #26679

PR-URL: #26915
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Signed-off-by: Beth Griggs <Bethany.Griggs@uk.ibm.com>

Author: BridgeAR

benchmark/fs/readfile-partitioned.js

@@ -29,7 +29,7 @@ function main(conf) {
   fs.writeFileSync(filename, data);
   data = null;
 
-  var zipData = Buffer.alloc(1024, 'a');
+  const zipData = Buffer.alloc(1024, 'a');
 
   var reads = 0;
   var zips = 0;

benchmark/fs/write-stream-throughput.js

@@ -38,7 +38,7 @@ function main({ dur, encodingType, size }) {
   var started = false;
   var ended = false;
 
-  var f = fs.createWriteStream(filename);
+  const f = fs.createWriteStream(filename);
   f.on('drain', write);
   f.on('open', write);
   f.on('close', done);