benchmark: calibrate util.format

According to nodejs/performance#186
this benchmark takes 2 minute to run a single run.
So using calibrate-n script it suggests reduce it from 1e6 to 1e2

Author: brunocroh

benchmark/util/format.js

@@ -4,21 +4,28 @@ const util = require('util');
 const common = require('../common');
 
 const inputs = {
-  'string': ['Hello, my name is %s', 'Fred'],
+  string: ['Hello, my name is %s', 'Fred'],
   'string-2': ['Hello, %s is my name', 'Fred'],
-  'number': ['Hi, I was born in %d', 1989],
+  number: ['Hi, I was born in %d', 1989],
   'replace-object': ['An error occurred %j', { msg: 'This is an error' }],
-  'unknown': ['hello %a', 'test'],
+  unknown: ['hello %a', 'test'],
   'no-replace': [1, 2],
   'no-replace-2': ['foobar', 'yeah', 'mensch', 5],
   'only-objects': [{ msg: 'This is an error' }, { msg: 'This is an error' }],
   'many-%': ['replace%%%%s%%%%many%s%s%s', 'percent'],
-  'object-to-string': ['foo %s bar', { toString() { return 'bla'; } }],
+  'object-to-string': [
+    'foo %s bar',
+    {
+      toString() {
+        return 'bla';
+      },
+    },
+  ],
   'object-%s': ['foo %s bar', { a: true, b: false }],
 };
 
 const bench = common.createBenchmark(main, {
-  n: [1e6],
+  n: [100],
   type: Object.keys(inputs),
 });