test: minimize time for child_process benchmark

test-benchmark-child-process sometimes times out on Windows in CI.
Minimize the number of configurations that run so it will (hopefully)
not time out anymore. Set dur=0.

PR-URL: nodejs#12518
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

test/sequential/test-benchmark-child-process.js

@@ -8,9 +8,11 @@ const path = require('path');
 
 const runjs = path.join(__dirname, '..', '..', 'benchmark', 'run.js');
 
-const child = fork(runjs, ['--set', 'dur=0.1',
+const child = fork(runjs, ['--set', 'dur=0',
                            '--set', 'n=1',
                            '--set', 'len=1',
+                           '--set', 'params=1',
+                           '--set', 'methodName=execSync',
                            'child_process'],
                    {env: {NODEJS_BENCHMARK_ZERO_ALLOWED: 1}});
 child.on('exit', (code, signal) => {