benchmark: remove deprecated argument

The benchmarks for dns.lookup() include calling it with an empty
hostname which results in a deprecation warning. This benchmark seems to
be subject to some odd side effects (see Ref below) and we probably
generally don't want to benchmark deprecated things by default anyway.
Remove the deprecated value from the default list. Bonus is that this
will speed up the benchmark.

Refs: https://github.com/nodejs/node/pull/27081#issuecomment-479981874

PR-URL: https://github.com/nodejs/node/pull/27091
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

benchmark/dns/lookup.js

@@ -4,7 +4,7 @@ const common = require('../common.js');
 const lookup = require('dns').lookup;
 
 const bench = common.createBenchmark(main, {
-  name: ['', '127.0.0.1', '::1'],
+  name: ['127.0.0.1', '::1'],
   all: ['true', 'false'],
   n: [5e6]
 });