Cleanup handles more efficiently, ensures we don't have to iterate over them

runtime/vm/benchmark_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/benchmark_test.h"
 
 #include "bin/file.h"
 
 #include "platform/assert.h"
 
@@ skipping 254 matching lines @@
 static Dart_NativeFunction NativeResolver(Dart_Handle name,
                                           int arg_count) {
   return &func;
 }
 
 
 BENCHMARK(Dart2JSCompileAll) {
   char* dart_root = ComputeDart2JSPath(Benchmark::Executable());
   char* script = NULL;
   if (dart_root != NULL) {
+    Isolate* isolate = Isolate::Current();
+    HANDLESCOPE(isolate);
     const char* kFormatStr =
         "import '%s/sdk/lib/_internal/compiler/compiler.dart';";
     intptr_t len = OS::SNPrint(NULL, 0, kFormatStr, dart_root) + 1;
     script = reinterpret_cast<char*>(malloc(len));
     EXPECT(script != NULL);
     OS::SNPrint(script, len, kFormatStr, dart_root);
     Dart_Handle lib = TestCase::LoadTestScript(
         script,
         reinterpret_cast<Dart_NativeEntryResolver>(NativeResolver));
     EXPECT_VALID(lib);
@@ skipping 97 matching lines @@
   Dart_Handle cls = Dart_GetClass(lib, NewString("StackFrameTest"));
   Dart_Handle result = Dart_Invoke(cls, NewString("testMain"), 0, NULL);
   EXPECT_VALID(result);
   int64_t elapsed_time = 0;
   result = Dart_IntegerToInt64(result, &elapsed_time);
   EXPECT_VALID(result);
   benchmark->set_score(elapsed_time);
 }
 
 }  // namespace dart