[heap] Fix finalization of incremental marking race.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index e1fa2fcf22579e5f6f7014725a8e617ed3e709b3..cbfe24b4921e4a8fea36976a439770b56a06b7f6 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -764,7 +764,8 @@ void Heap::HandleGCRequest() {
     return;
   }
   DCHECK(FLAG_finalize_marking_incrementally);
-  if (!incremental_marking()->finalize_marking_completed()) {
+  if (incremental_marking()->IsMarking() &&
+      !incremental_marking()->finalize_marking_completed()) {
     FinalizeIncrementalMarking("GC interrupt: finalize incremental marking");
   }
 }