Represent tokens as a compressed stream instead of an array.

vm/benchmark_test.cc

Index: vm/benchmark_test.cc
===================================================================
--- vm/benchmark_test.cc	(revision 9536)
+++ vm/benchmark_test.cc	(working copy)
@@ -173,14 +173,21 @@
       1);
   EXPECT(!Dart_IsError(result));
 
-  Timer timer(true, "UseDartApi benchmark");
-  timer.Start();
   Dart_Handle args[1];
   args[0] = Dart_NewInteger(kNumIterations);
+
+  // Warmup first to avoid compilation jitters.
   Dart_Invoke(lib,
               Dart_NewString("benchmark"),
               1,
               args);
+
+  Timer timer(true, "UseDartApi benchmark");
+  timer.Start();
+  Dart_Invoke(lib,
+              Dart_NewString("benchmark"),
+              1,
+              args);
   timer.Stop();
   int64_t elapsed_time = timer.TotalElapsedTime();
   benchmark->set_score(elapsed_time);