Limit the number of benchmark trials.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1327733002 .

pkgs/yaml/benchmark/benchmark.dart

diff --git a/pkgs/yaml/benchmark/benchmark.dart b/pkgs/yaml/benchmark/benchmark.dart
index aec6d4b..388fccb 100644
--- a/pkgs/yaml/benchmark/benchmark.dart
+++ b/pkgs/yaml/benchmark/benchmark.dart
@@ -11,7 +11,7 @@
 
 import 'package:yaml/yaml.dart';
 
-const numTrials = 10000000;
+const numTrials = 100;
 const runsPerTrial = 1000;
 
 final source = loadFile("input.yaml");