Move CompilerStats from isolate to thread. Aggregate stats.

runtime/vm/benchmark_test.cc

Index: runtime/vm/benchmark_test.cc
diff --git a/runtime/vm/benchmark_test.cc b/runtime/vm/benchmark_test.cc
index 1c59f8dbea52baec1fe3415f98e60df98d225161..77503755923c405e43ff81c631d834bcbbffa2c9 100644
--- a/runtime/vm/benchmark_test.cc
+++ b/runtime/vm/benchmark_test.cc
@@ -138,7 +138,7 @@ BENCHMARK(CorelibCompilerStats) {
   bin::Builtin::SetNativeResolver(bin::Builtin::kBuiltinLibrary);
   bin::Builtin::SetNativeResolver(bin::Builtin::kIOLibrary);
   TransitionNativeToVM transition(thread);
-  CompilerStats* stats = thread->isolate()->compiler_stats();
+  CompilerStats* stats = thread->isolate()->aggregate_compiler_stats();
   ASSERT(stats != NULL);
   stats->EnableBenchmark();
   Timer timer(true, "Compiler stats compiling all of Core lib");
@@ -174,7 +174,7 @@ BENCHMARK(Dart2JSCompilerStats) {
         reinterpret_cast<Dart_NativeEntryResolver>(NativeResolver));
     EXPECT_VALID(lib);
   }
-  CompilerStats* stats = thread->isolate()->compiler_stats();
+  CompilerStats* stats = thread->isolate()->aggregate_compiler_stats();
   ASSERT(stats != NULL);
   stats->EnableBenchmark();
   Timer timer(true, "Compile all of dart2js benchmark");