[heap] Tracer: Fix accounting for external epilogue

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index c39b51ab5ea41fb44e440d03ce53537e277af4dc..e5c54621c94d4636400f06b0c59c6dc14f73b5fe 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -840,7 +840,7 @@ void Heap::FinalizeIncrementalMarking(const char* gc_reason) {
     if (scope.CheckReenter()) {
       AllowHeapAllocation allow_allocation;
       GCTracer::Scope scope(tracer(),
-                            GCTracer::Scope::MC_INCREMENTAL_EXTERNAL_PROLOGUE);
+                            GCTracer::Scope::MC_INCREMENTAL_EXTERNAL_EPILOGUE);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
       CallGCEpilogueCallbacks(kGCTypeIncrementalMarking, kNoGCCallbackFlags);