benchmark: shorten pipe-to by reducing number of chunks

PR-URL: #49577
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Debadree Chatterjee <debadree333@gmail.com>

benchmark/webstreams/pipe-to.js

@@ -6,7 +6,7 @@ const {
 } = require('node:stream/web');
 
 const bench = common.createBenchmark(main, {
-  n: [5e6],
+  n: [5e5],
   highWaterMarkR: [512, 1024, 2048, 4096],
   highWaterMarkW: [512, 1024, 2048, 4096],
 });