[heap] Add GC accounting to slow allocation and incremental marking job

src/heap/incremental-marking-job.cc

Index: src/heap/incremental-marking-job.cc
diff --git a/src/heap/incremental-marking-job.cc b/src/heap/incremental-marking-job.cc
index 393b9cce7eeace05b893679d448bfb54490261df..5631266f8df2e6b402bc9602b93c476e542d40b9 100644
--- a/src/heap/incremental-marking-job.cc
+++ b/src/heap/incremental-marking-job.cc
@@ -42,6 +42,9 @@ void IncrementalMarkingJob::Task::Step(Heap* heap) {
 }
 
 void IncrementalMarkingJob::Task::RunInternal() {
+  VMState<GC> state(isolate());
+  RuntimeCallTimerScope(isolate(), &RuntimeCallStats::GC);
+
   Heap* heap = isolate()->heap();
   job_->NotifyTask();
   IncrementalMarking* incremental_marking = heap->incremental_marking();