Use weak cell to embed map in CompareNil IC.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 9d17f1f8bd4e6f9275c00b106dee86174b2edae1..f3090011809f2380ddae0249ef8919fd26b604ba 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -10824,7 +10824,9 @@ void Code::FindAndReplace(const FindAndReplacePattern& pattern) {
     RelocInfo* info = it.rinfo();
     Object* object = info->target_object();
     if (object->IsHeapObject()) {
-      DCHECK(!object->IsWeakCell());
+      if (object->IsWeakCell()) {
+        object = HeapObject::cast(WeakCell::cast(object)->value());
+      }
       Map* map = HeapObject::cast(object)->map();
       if (map == *pattern.find_[current_pattern]) {
         info->set_target_object(*pattern.replace_[current_pattern]);