Access old space marking bits from runtime only when incremental marking is in MARKING state.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 916c99371938da6f63eea6eea42525cc1afd0c00..e2c61556dabf10123291b8a436c4a76e7b16aa23 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -4125,8 +4125,10 @@ MUST_USE_RESULT static MaybeObject* StringReplaceGlobalRegExpWithEmptyString(
   if (delta == 0) return *answer;
 
   Address end_of_string = answer->address() + string_size;
-  isolate->heap()->CreateFillerObjectAt(end_of_string, delta);
-  if (Marking::IsBlack(Marking::MarkBitFrom(*answer))) {
+  Heap* heap = isolate->heap();
+  heap->CreateFillerObjectAt(end_of_string, delta);
+  if (heap->incremental_marking()->IsMarking() &&
+      Marking::IsBlack(Marking::MarkBitFrom(*answer))) {
     MemoryChunk::IncrementLiveBytesFromMutator(answer->address(), -delta);
   }