test: add test-benchmark-policy

Add test-benchmark-policy for new policy benchmarks. The benchmark tests
help us make sure that code changes don't break benchmarks so we can
make sure benchmarks get updated (or removed) as appropriate.

Author: Trott

test/benchmark/test-benchmark-policy.js

@@ -0,0 +1,9 @@
+'use strict';
+
+require('../common');
+
+const runBenchmark = require('../common/benchmark');
+
+runBenchmark('policy', [
+  'n=1',
+]);