test: fix flaky test-benchmark-querystring

Allow zero iterations for short benchmark in test.

PR-URL: https://github.com/nodejs/node/pull/17517
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

test/parallel/test-benchmark-querystring.js

@@ -4,8 +4,9 @@ require('../common');
 
 const runBenchmark = require('../common/benchmark');
 
-runBenchmark('querystring', [
-  'n=1',
+runBenchmark('querystring',
+             [ 'n=1',
                'input="there is nothing to unescape here"',
                'type=noencode'
-]);
+             ],
+             { NODEJS_BENCHMARK_ZERO_ALLOWED: 1 });