benchmark: update iterations in benchmark/util/splice-one.js

Increase the number of iterations from 1e5 to 5e6
to avoid the test performance gap caused by inactive
V8 optimization caused by insufficient number of iterations

Refs: #50571
PR-URL: #50698
Reviewed-By: Vinícius Lourenço Claro Cardoso <contact@viniciusl.com.br>

benchmark/util/splice-one.js

@@ -3,7 +3,7 @@
 const common = require('../common');
 
 const bench = common.createBenchmark(main, {
- n: [1e5],
+ n: [5e6],
  pos: ['start', 'middle', 'end'],
  size: [10, 100, 500],
 }, { flags: ['--expose-internals'] });