Fix CompilerStats aggregation: do not aggregate if there is no mutator thread (isolate shutting dow…

runtime/vm/profiler_test.cc

 // Copyright (c) 2013, 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 "platform/assert.h"
 
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_state.h"
 #include "vm/globals.h"
 #include "vm/profiler.h"
@@ skipping 1091 matching lines @@
     AllocationFilter filter(isolate, one_byte_string_class.id());
     profile.Build(thread, &filter, Profile::kNoTags);
     // We should now have two allocation samples.
     EXPECT_EQ(2, profile.sample_count());
   }
 }
 
 
 TEST_CASE(Profiler_StringInterpolation) {
   DisableNativeProfileScope dnps;
+  DisableBackgroundCompilationScope dbcs;
   const char* kScript = "String foo(String a, String b) => '$a | $b';";
   Dart_Handle lib = TestCase::LoadTestScript(kScript, NULL);
   EXPECT_VALID(lib);
   Library& root_library = Library::Handle();
   root_library ^= Api::UnwrapHandle(lib);
   Isolate* isolate = thread->isolate();
 
   const Class& one_byte_string_class =
       Class::Handle(isolate->object_store()->one_byte_string_class());
   EXPECT(!one_byte_string_class.IsNull());
@@ skipping 1372 matching lines @@
   EXPECT_SUBSTRING("\"positions\":[\"TempMove\",39]", js.ToCString());
   // Verify exclusive ticks in main.
   EXPECT_SUBSTRING("\"exclusiveTicks\":[1,0]", js.ToCString());
   // Verify inclusive ticks in main.
   EXPECT_SUBSTRING("\"inclusiveTicks\":[1,2]", js.ToCString());
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart